0:00:00.410,0:00:03.900 Where we left off after the[br]meiosis videos is that we had 0:00:03.900,0:00:04.960 two gametes. 0:00:04.960,0:00:07.110 We had a sperm and an egg. 0:00:07.110,0:00:08.350 Let me draw the sperm. 0:00:08.350,0:00:11.790 So you had the sperm and[br]then you had an egg. 0:00:11.790,0:00:14.810 Maybe I'll do the egg in[br]a different color. 0:00:14.810,0:00:18.700 That's the egg, and we all[br]know how this story goes. 0:00:18.700,0:00:20.390 The sperm fertilizes the egg. 0:00:20.390,0:00:23.490 And a whole cascade of events[br]start occurring. 0:00:23.490,0:00:27.060 The walls of the egg then become[br]impervious to other 0:00:27.060,0:00:30.190 sperm so that only one sperm can[br]get in, but that's not the 0:00:30.190,0:00:31.120 focus of this video. 0:00:31.120,0:00:35.300 The focus of this video is how[br]this fertilized egg develops 0:00:35.300,0:00:38.840 once it has become a zygote. 0:00:38.840,0:00:42.920 So after it's fertilized, you[br]remember from the meiosis 0:00:42.920,0:00:48.680 videos that each of these were[br]haploid, or that they had-- 0:00:48.680,0:00:51.570 oh, I added an extra i there--[br]that they had half the 0:00:51.570,0:00:56.450 contingency of the DNA. 0:00:56.450,0:01:00.685 As soon as the sperm fertilizes[br]this egg, now, all 0:01:00.685,0:01:03.260 of a sudden, you have[br]a diploid zygote. 0:01:03.260,0:01:04.099 Let me do that. 0:01:04.099,0:01:07.160 So now let me pick[br]a nice color. 0:01:07.160,0:01:10.620 So now you're going to have a[br]diploid zygote that's going to 0:01:10.620,0:01:16.570 have a 2N complement of the DNA[br]material or kind of the 0:01:16.570,0:01:20.320 full complement of what a normal[br]cell in our human body 0:01:20.320,0:01:25.320 would have. So this is diploid,[br]and it's a zygote, 0:01:25.320,0:01:30.030 which is just a fancy way of[br]saying the fertilized egg. 0:01:30.030,0:01:31.570 And it's now ready[br]to essentially 0:01:31.570,0:01:33.390 turn into an organism. 0:01:33.390,0:01:36.570 So immediately after[br]fertilization, this zygote 0:01:36.570,0:01:39.470 starts experiencing cleavage. 0:01:39.470,0:01:42.620 It's experiencing mitosis,[br]that's the mechanism, but it 0:01:42.620,0:01:44.170 doesn't increase[br]a lot in size. 0:01:44.170,0:01:48.860 So this one right here will then[br]turn into-- it'll just 0:01:48.860,0:01:52.030 split up via mitosis[br]into two like that. 0:01:52.030,0:01:55.280 And, of course, these are each[br]2N, and then those are going 0:01:55.280,0:02:01.510 to split into four like that. 0:02:01.510,0:02:05.920 And each of these have the same[br]exact genetic complement 0:02:05.920,0:02:08.750 as that first zygote, and[br]it keeps splitting. 0:02:08.750,0:02:14.930 And this mass of cells, we can[br]start calling it, this right 0:02:14.930,0:02:17.455 here, this is referred[br]to as the morula. 0:02:20.550,0:02:22.910 And actually, it comes from the[br]word for mulberry because 0:02:22.910,0:02:24.250 it looks like a mulberry. 0:02:24.250,0:02:26.930 So actually, let me just kind[br]of simplify things a little 0:02:26.930,0:02:28.450 bit because we don't[br]have to start here. 0:02:28.450,0:02:29.700 So we start with a zygote. 0:02:32.240,0:02:33.215 This is a fertilized egg. 0:02:33.215,0:02:38.080 It just starts duplicating via[br]mitosis, and you end up with a 0:02:38.080,0:02:40.860 ball of cells. 0:02:40.860,0:02:43.680 It's often going to be a power[br]of two, because these cells, 0:02:43.680,0:02:46.890 at least in the initial stages[br]are all duplicating all at 0:02:46.890,0:02:48.230 once, and then you[br]have this morula. 0:02:51.290,0:02:54.850 Now, once the morula gets to[br]about 16 cells or so-- and 0:02:54.850,0:02:56.550 we're talking about[br]four or five days. 0:02:56.550,0:03:01.720 This isn't an exact process--[br]they started differentiating a 0:03:01.720,0:03:04.510 little bit, where the outer[br]cells-- and this kind of turns 0:03:04.510,0:03:05.450 into a sphere. 0:03:05.450,0:03:08.880 Let me make it a little[br]bit more sphere like. 0:03:08.880,0:03:12.650 So it starts differentiating[br]between-- let me make some 0:03:12.650,0:03:13.380 outer cells. 0:03:13.380,0:03:15.200 This would be a cross-section[br]of it. 0:03:15.200,0:03:18.150 It's really going to look[br]more like a sphere. 0:03:18.150,0:03:22.950 That's the outer cells and then[br]you have your inner cells 0:03:22.950,0:03:24.980 on the inside. 0:03:24.980,0:03:32.930 These outer cells are called[br]the trophoblasts. 0:03:32.930,0:03:34.560 Let me do it in a[br]different color. 0:03:40.896,0:03:42.480 Let me scroll over. 0:03:42.480,0:03:43.250 I don't want to go there. 0:03:43.250,0:03:46.430 And then the inner cells, and[br]this is kind of the crux of 0:03:46.430,0:03:48.550 what this video is all[br]about-- let me scroll 0:03:48.550,0:03:49.450 down a little bit. 0:03:49.450,0:03:54.530 The inner cells-- pick[br]a suitable color. 0:03:54.530,0:04:01.590 The inner cells right there are[br]called the embryoblast. 0:04:01.590,0:04:03.660 And then what's going to happen[br]is some fluid's going 0:04:03.660,0:04:06.130 to start filling in some[br]of this gap between the 0:04:06.130,0:04:08.790 embryoblast and the trophoblast,[br]so you're going 0:04:08.790,0:04:14.160 to start having some fluid that[br]comes in there, and so 0:04:14.160,0:04:18.029 the morula will eventually[br]look like this, where the 0:04:18.029,0:04:21.480 trophoblast, or the outer[br]membrane, is kind of this huge 0:04:21.480,0:04:22.760 sphere of cells. 0:04:22.760,0:04:25.680 And this is all happening as[br]they keep replicating. 0:04:25.680,0:04:29.620 Mitosis is the mechanism, so now[br]my trophoblast is going to 0:04:29.620,0:04:34.680 look like that, and then[br]my embryoblast is going 0:04:34.680,0:04:36.620 to look like this. 0:04:36.620,0:04:46.160 Sometimes the embryoblast-- so[br]this is the embryoblast. 0:04:46.160,0:04:51.320 Sometimes it's also called the[br]inner cell mass, so let me 0:04:51.320,0:04:52.570 write that. 0:04:56.450,0:04:58.950 And this is what's going to[br]turn into the organism. 0:04:58.950,0:05:01.390 And so, just so you know a[br]couple of the labels that are 0:05:01.390,0:05:03.910 involved here, if we're dealing[br]with a mammalian 0:05:03.910,0:05:07.710 organism, and we are mammals,[br]we call this thing that the 0:05:07.710,0:05:10.690 morula turned into is a zygote,[br]then a morula, then 0:05:10.690,0:05:13.720 the cells of the morula started[br]to differentiate into 0:05:13.720,0:05:16.190 the trophoblast, or kind of the[br]outside cells, and then 0:05:16.190,0:05:22.760 the embryoblast. And then you[br]have this space that forms 0:05:22.760,0:05:26.960 here, and this is just fluid,[br]and it's called the 0:05:26.960,0:05:28.210 blastocoel. 0:05:32.510,0:05:35.890 A very non-intuitive spelling[br]of the coel part of 0:05:35.890,0:05:37.430 blastocoel. 0:05:37.430,0:05:40.280 But once this is formed, this is[br]called a blastocyst. That's 0:05:40.280,0:05:41.800 the entire thing right here. 0:05:41.800,0:05:44.460 Let me scroll down[br]a little bit. 0:05:44.460,0:05:49.870 This whole thing is called the[br]blastocyst, and this is the 0:05:49.870,0:05:51.120 case in humans. 0:05:54.070,0:05:57.120 Now, it can be a very confusing[br]topic, because a lot 0:05:57.120,0:05:59.940 of times in a lot of books on[br]biology, you'll say, hey, you 0:05:59.940,0:06:02.580 go from the morula to[br]the blastula or the 0:06:02.580,0:06:04.280 blastosphere stage. 0:06:04.280,0:06:06.740 Let me write those words down. 0:06:06.740,0:06:10.000 So sometimes you'll say morula, 0:06:10.000,0:06:11.250 and you go to blastula. 0:06:14.400,0:06:15.760 Sometimes it's called[br]the blastosphere. 0:06:20.120,0:06:22.550 And I want to make it very[br]clear that these are 0:06:22.550,0:06:25.630 essentially the same stages[br]in development. 0:06:25.630,0:06:28.860 These are just for-- you know,[br]in a lot of books, they'll 0:06:28.860,0:06:32.100 start talking about frogs or[br]tadpoles or things like that, 0:06:32.100,0:06:33.440 and this applies to them. 0:06:33.440,0:06:35.890 While we're talking about[br]mammals, especially the ones 0:06:35.890,0:06:38.330 that are closely related[br]to us, the stage is the 0:06:38.330,0:06:41.240 blastocyst stage, and the real[br]differentiator is when people 0:06:41.240,0:06:44.360 talk about just blastula[br]and blastospheres. 0:06:44.360,0:06:47.290 There isn't necessarily this[br]differentiation between these 0:06:47.290,0:06:51.480 outermost cells and these[br]embryonic, or this 0:06:51.480,0:06:54.290 embryoblast, or this inner[br]cell mass here. 0:06:54.290,0:06:57.350 But since the focus of this[br]video is humans, and really 0:06:57.350,0:06:59.620 that's where I wanted to start[br]from, because that's what we 0:06:59.620,0:07:01.420 are and that's what's[br]interesting, we're going to 0:07:01.420,0:07:03.810 focus on the blastocyst. 0:07:03.810,0:07:06.310 Now, everything I've talked[br]about in this video, it was 0:07:06.310,0:07:10.360 really to get to this point,[br]because what we have here, 0:07:10.360,0:07:14.270 these little green cells that[br]I drew right here in the 0:07:14.270,0:07:18.210 blastocysts, this inner cell[br]mass, this is what will turn 0:07:18.210,0:07:19.200 into the organism. 0:07:19.200,0:07:21.250 And you say, OK, Sal, if that's[br]the organism, what's 0:07:21.250,0:07:24.980 all of these purple[br]cells out here? 0:07:24.980,0:07:27.210 This trophoblast out there? 0:07:27.210,0:07:30.880 That is going to turn into the[br]placenta, and I'll do a future 0:07:30.880,0:07:34.595 video where in a human, it'll[br]turn into a placenta. 0:07:34.595,0:07:35.970 So let me write that down. 0:07:35.970,0:07:38.250 It'll turn into the placenta. 0:07:38.250,0:07:41.600 And I'll do a whole future video[br]about I guess how babies 0:07:41.600,0:07:44.320 are born, and I actually learned[br]a ton about that this 0:07:44.320,0:07:47.580 past year because a baby[br]was born in our house. 0:07:47.580,0:07:51.320 But the placenta is really[br]kind of what the embryo 0:07:51.320,0:07:54.880 develops inside of, and it's the[br]interface, especially in 0:07:54.880,0:07:59.260 humans and in mammals, between[br]the developing fetus and its 0:07:59.260,0:08:02.220 mother, so it kind of is the[br]exchange mechanism that 0:08:02.220,0:08:05.200 separates their two systems,[br]but allows the necessary 0:08:05.200,0:08:06.790 functions to go on[br]between them. 0:08:06.790,0:08:08.860 But that's not the focus[br]of this video. 0:08:08.860,0:08:12.680 The focus of this video is the[br]fact that these cells, which 0:08:12.680,0:08:15.870 at this point are-- they've[br]differentiated themselves away 0:08:15.870,0:08:18.560 from the placenta cells, but[br]they still haven't decided 0:08:18.560,0:08:20.540 what they're going to become. 0:08:20.540,0:08:24.210 Maybe this cell and its[br]descendants eventually start 0:08:24.210,0:08:27.640 becoming part of the nervous[br]system, while these cells 0:08:27.640,0:08:31.540 right here might become muscle[br]tissue, while these cells 0:08:31.540,0:08:36.750 right here might become[br]the liver. 0:08:36.750,0:08:40.740 These cells right here are[br]called embryonic stem cells, 0:08:40.740,0:08:43.120 and probably the first time in[br]this video you're hearing a 0:08:43.120,0:08:45.440 term that you might recognize. 0:08:45.440,0:08:48.220 So if I were to just take one of[br]these cells, and actually, 0:08:48.220,0:08:52.890 just to introduce you to another[br]term, you know, we 0:08:52.890,0:08:54.770 have this zygote. 0:08:54.770,0:08:59.030 As soon as it starts dividing,[br]each of these cells are called 0:08:59.030,0:09:00.930 a blastomere. 0:09:00.930,0:09:04.020 And you're probably wondering,[br]Sal, why does this word blast 0:09:04.020,0:09:08.210 keep appearing in this kind[br]of embryology video, these 0:09:08.210,0:09:09.130 development videos? 0:09:09.130,0:09:13.480 And that comes from the Greek[br]for spore: blastos. 0:09:13.480,0:09:19.030 So the organism is beginning[br]to spore out or grow. 0:09:19.030,0:09:21.610 I won't go into the word origins[br]of it, but that's 0:09:21.610,0:09:23.030 where it comes from and that's[br]why everything has 0:09:23.030,0:09:23.860 this blast in it. 0:09:23.860,0:09:25.680 So these are blastomeres. 0:09:25.680,0:09:28.970 So when I talk what embryonic[br]stem cells, I'm talking about 0:09:28.970,0:09:34.330 the individual blastomeres[br]inside of this embryoblast or 0:09:34.330,0:09:36.890 inside of this inner[br]cell mass. 0:09:36.890,0:09:39.780 These words are actually[br]unusually fun to say. 0:09:39.780,0:09:43.160 So each of these is an[br]embryonic stem cell. 0:09:43.160,0:09:47.120 Let me write this down[br]in a vibrant color. 0:09:47.120,0:09:52.190 So each of these right here are[br]embryonic stem cells, and 0:09:52.190,0:09:53.440 I wanted to get to this. 0:09:56.440,0:09:58.530 And the reason why these are[br]interesting, and I think you 0:09:58.530,0:10:00.760 already know, is that there's[br]a huge debate around these. 0:10:00.760,0:10:03.830 One, these have the potential[br]to turn into anything, that 0:10:03.830,0:10:05.950 they have this plasticity. 0:10:05.950,0:10:07.410 That's another word that[br]you might hear. 0:10:07.410,0:10:09.455 Let me write that down,[br]too: plasticity. 0:10:12.050,0:10:14.920 And the word essentially comes[br]from, you know, like a plastic 0:10:14.920,0:10:17.130 can turn into anything else. 0:10:17.130,0:10:19.630 When we say that something has[br]plasticity, we're talking 0:10:19.630,0:10:21.780 about its potential[br]to turn into a lot 0:10:21.780,0:10:22.620 of different things. 0:10:22.620,0:10:26.380 So the theory is, and there's[br]already some trials that seem 0:10:26.380,0:10:28.390 to substantiate this, especially[br]in some lower 0:10:28.390,0:10:31.070 organisms, that, look, if you[br]have some damage at some point 0:10:31.070,0:10:36.460 in your body-- let me[br]draw a nerve cell. 0:10:36.460,0:10:40.590 Let me say I have a-- I won't[br]go into the actual mechanics 0:10:40.590,0:10:43.790 of a nerve cell, but let's say[br]that we have some damage at 0:10:43.790,0:10:46.980 some point on a nerve cell right[br]there, and because of 0:10:46.980,0:10:50.450 that, someone is paralyzed[br]or there's some nerve 0:10:50.450,0:10:51.400 dysfunction. 0:10:51.400,0:10:54.330 We're dealing with multiple[br]sclerosis or who knows what. 0:10:54.330,0:10:57.280 The idea is, look, we have these[br]cell here that could 0:10:57.280,0:11:02.650 turn into anything, and we're[br]just really understanding how 0:11:02.650,0:11:04.410 it knows what to turn into. 0:11:04.410,0:11:06.550 It really has to look at its[br]environment and say, hey, what 0:11:06.550,0:11:08.900 are the guys around me doing,[br]and maybe that's what helps 0:11:08.900,0:11:10.150 dictate what it does. 0:11:10.150,0:11:12.500 But the idea is you take these[br]things that could turn to 0:11:12.500,0:11:16.740 anything and you put them where[br]the damage is, you layer 0:11:16.740,0:11:19.910 them where the damage is, and[br]then they can turn into the 0:11:19.910,0:11:21.510 cell that they need[br]to turn into. 0:11:21.510,0:11:24.990 So in this case, they would[br]turn into nerve cells. 0:11:24.990,0:11:29.220 They would turn to nerve cells[br]and repair the damage and 0:11:29.220,0:11:32.480 maybe cure the paralysis[br]for that individual. 0:11:32.480,0:11:35.640 So it's a huge, exciting area[br]of research, and you could 0:11:35.640,0:11:37.700 even, in theory, grow[br]new organs. 0:11:37.700,0:11:39.800 If someone needs a kidney[br]transplant or a heart 0:11:39.800,0:11:43.690 transplant, maybe in the future,[br]we could take a colony 0:11:43.690,0:11:44.980 of these embryonic stem cells. 0:11:44.980,0:11:48.510 Maybe we can put them in some[br]type of other creature, or who 0:11:48.510,0:11:52.050 knows what, and we can turn it[br]into a replacement heart or a 0:11:52.050,0:11:52.660 replacement kidney. 0:11:52.660,0:11:56.480 So there's a huge amount[br]of excitement about 0:11:56.480,0:11:57.420 what these can do. 0:11:57.420,0:12:01.310 I mean, they could cure a lot of[br]formerly uncurable diseases 0:12:01.310,0:12:03.350 or provide hope for a[br]lot of patients who 0:12:03.350,0:12:05.120 might otherwise die. 0:12:05.120,0:12:07.870 But obviously, there's[br]a debate here. 0:12:07.870,0:12:10.950 And the debate all revolves[br]around the issue of if you 0:12:10.950,0:12:15.120 were to go in here and try to[br]extract one of these cells, 0:12:15.120,0:12:17.560 you're going to kill[br]this embryo. 0:12:17.560,0:12:21.160 You're going to kill this[br]developing embryo, and that 0:12:21.160,0:12:23.670 developing embryo had[br]the potential to 0:12:23.670,0:12:27.140 become a human being. 0:12:27.140,0:12:28.880 It's a potential that obviously[br]has to be in the 0:12:28.880,0:12:33.520 right environment, and it has[br]to have a willing mother and 0:12:33.520,0:12:35.820 all of the rest, but it does[br]have the potential. 0:12:35.820,0:12:40.370 And so for those, especially, I[br]think, in the pro-life camp, 0:12:40.370,0:12:44.280 who say, hey, anything that has[br]a potential to be a human 0:12:44.280,0:12:47.310 being, that is life and it[br]should not be killed. 0:12:47.310,0:12:52.510 So people on that side of the[br]camp, they're against the 0:12:52.510,0:12:54.510 destroying of this embryo. 0:12:54.510,0:12:57.880 I'm not making this video to[br]take either side to that 0:12:57.880,0:13:01.740 argument, but it's a potential[br]to turn to a human being. 0:13:01.740,0:13:04.010 It's a potential, right? 0:13:04.010,0:13:07.730 So obviously, there's a huge[br]amount of debate, but now, now 0:13:07.730,0:13:10.310 you know in this video what[br]people are talking about when 0:13:10.310,0:13:12.690 they say embryonic stem cells. 0:13:12.690,0:13:14.680 And obviously, the next question[br]is, hey, well, why 0:13:14.680,0:13:16.910 don't they just call them stem[br]cells as opposed to embryonic 0:13:16.910,0:13:17.490 stem cells? 0:13:17.490,0:13:20.875 And that's because in all of our[br]bodies, you do have what 0:13:20.875,0:13:22.850 are called somatic stem cells. 0:13:22.850,0:13:24.850 Let me write that down. 0:13:24.850,0:13:29.000 Somatic or adults stem cells. 0:13:29.000,0:13:30.100 And we all have them. 0:13:30.100,0:13:32.860 They're in our bone marrow to[br]help produce red blood cells, 0:13:32.860,0:13:36.160 other parts of our body, but the[br]problem with somatic stem 0:13:36.160,0:13:41.780 cells is they're not as plastic,[br]which means that they 0:13:41.780,0:13:44.810 can't form any type of cell[br]in the human body. 0:13:44.810,0:13:46.880 There's an area of research[br]where people are actually 0:13:46.880,0:13:50.470 maybe trying to make them more[br]plastic, and if they are able 0:13:50.470,0:13:52.900 to take these somatic stem[br]cells and make them more 0:13:52.900,0:13:56.290 plastic, it might maybe kill[br]the need to have these 0:13:56.290,0:13:58.660 embryonic stem cells, although[br]maybe if they do this too 0:13:58.660,0:14:01.690 good, maybe these will have[br]the potential to turn into 0:14:01.690,0:14:03.010 human beings as well,[br]so that could 0:14:03.010,0:14:04.770 become a debatable issue. 0:14:04.770,0:14:08.130 But right now, this isn't an[br]area of debate because, left 0:14:08.130,0:14:12.510 to their own devices, a somatic[br]stem cell or an adult 0:14:12.510,0:14:15.420 stem cell won't turn into[br]a human being, while an 0:14:15.420,0:14:19.760 embryonic one, if it is[br]implanted in a willing mother, 0:14:19.760,0:14:21.970 then, of course, it will turn[br]into a human being. 0:14:21.970,0:14:24.210 And I want to make one side[br]note here, because I don't 0:14:24.210,0:14:30.410 want to take any sides on the[br]debate of-- well, I mean, 0:14:30.410,0:14:31.250 facts are facts. 0:14:31.250,0:14:33.900 This does have the potential[br]to turn into a human being, 0:14:33.900,0:14:36.980 but it also has the potential[br]to save millions of lives. 0:14:36.980,0:14:39.740 Both of those statements are[br]facts, and then you can decide 0:14:39.740,0:14:42.960 on your own which side of that[br]argument you'd like to or what 0:14:42.960,0:14:45.670 side of that balance you[br]would like to kind of 0:14:45.670,0:14:47.210 put your own opinion. 0:14:47.210,0:14:50.020 But there's one thing I want[br]to talk about that in the 0:14:50.020,0:14:51.890 public debate is never[br]brought up. 0:14:51.890,0:14:55.600 So you have this notion of when[br]you-- to get an embryonic 0:14:55.600,0:14:58.570 stem cell line, and when I say[br]a stem cell line, I mean you 0:14:58.570,0:15:00.880 take a couple of stem cells, or[br]let's say you take one stem 0:15:00.880,0:15:04.550 cell, and then you put it in a[br]Petri dish, and then you allow 0:15:04.550,0:15:06.650 it to just duplicate. 0:15:06.650,0:15:09.780 So this one turns into two,[br]those two turn to four. 0:15:09.780,0:15:12.380 Then someone could take one of[br]these and then put it in their 0:15:12.380,0:15:13.600 own Petri dish. 0:15:13.600,0:15:15.200 These are a stem cell line. 0:15:15.200,0:15:20.310 They all came from one unique[br]embryonic stem cell or what 0:15:20.310,0:15:21.950 initially was a blastomere. 0:15:21.950,0:15:24.500 So that's what they call[br]a stem cell line. 0:15:24.500,0:15:28.140 So the debate obviously is when[br]you start an embryonic 0:15:28.140,0:15:31.060 stem cell line, you are[br]destroying an embryo. 0:15:31.060,0:15:33.900 But I want to make the point[br]here that embryos are being 0:15:33.900,0:15:37.140 destroyed in other processes,[br]and namely, in-vitro 0:15:37.140,0:15:38.390 fertilization. 0:15:40.530,0:15:44.740 And maybe this'll be my next[br]video: fertilization. 0:15:44.740,0:15:48.690 And this is just the notion that[br]they take a set of eggs 0:15:48.690,0:15:49.515 out of a mother. 0:15:49.515,0:15:52.430 It's usually a couple that's[br]having trouble having a child, 0:15:52.430,0:15:54.280 and they take a bunch of[br]eggs out of the mother. 0:15:54.280,0:15:56.940 So let's say they take[br]maybe 10 to 30 0:15:56.940,0:15:59.000 eggs out of the mother. 0:15:59.000,0:16:02.460 They actually perform a surgery,[br]take them out of the 0:16:02.460,0:16:06.760 ovaries of the mother, and then[br]they fertilize them with 0:16:06.760,0:16:09.890 semen, either it might come[br]from the father or a sperm 0:16:09.890,0:16:13.210 donor, so then all of these[br]becomes zygotes once they're 0:16:13.210,0:16:15.090 fertilized with semen. 0:16:15.090,0:16:17.860 So these all become zygotes,[br]and then they allow them to 0:16:17.860,0:16:19.870 develop, and they usually allow[br]them to develop to the 0:16:19.870,0:16:21.480 blastocyst stage. 0:16:21.480,0:16:25.600 So eventually all of these[br]turn into blastocysts. 0:16:25.600,0:16:30.050 They have a blastocoel in[br]the center, which is 0:16:30.050,0:16:32.520 this area of fluid. 0:16:32.520,0:16:37.920 They have, of course, the[br]embryo, the inner cell mass in 0:16:37.920,0:16:41.310 them, and what they do is they[br]look at the ones that they 0:16:41.310,0:16:44.180 deem are healthier or maybe[br]the ones that are at least 0:16:44.180,0:16:47.400 just not unhealthy, and they'll[br]take a couple of these 0:16:47.400,0:16:50.160 and they'll implant these into[br]the mother, so all of this is 0:16:50.160,0:16:52.180 occurring in a Petri dish. 0:16:52.180,0:16:55.270 So maybe these four look good,[br]so they're going to take these 0:16:55.270,0:16:57.840 four, and they're going to[br]implant these into a mother, 0:16:57.840,0:17:01.070 and if all goes well, maybe one[br]of these will turn into-- 0:17:01.070,0:17:02.670 will give the couple a child. 0:17:02.670,0:17:05.180 So this one will develop and[br]maybe the other ones won't. 0:17:05.180,0:17:09.520 But if you've seen John & Kate[br]Plus 8, you know that many 0:17:09.520,0:17:12.349 times they implant a lot of[br]them in there, just to 0:17:12.349,0:17:14.520 increase the probability that[br]you get at least one child. 0:17:14.520,0:17:17.310 But every now and then, they[br]implant seven or eight, and 0:17:17.310,0:17:18.680 then you end up with[br]eight kids. 0:17:18.680,0:17:21.150 And that's why in-vitro[br]fertilization often results in 0:17:21.150,0:17:25.359 kind of these multiple[br]births, or reality 0:17:25.359,0:17:27.270 television shows on cable. 0:17:27.270,0:17:30.330 But what do they do with all[br]of these other perfectly-- 0:17:30.330,0:17:33.110 well, I won't say perfectly[br]viable, but these are embryos. 0:17:33.110,0:17:36.350 They may or may not be perfectly[br]viable, but you have 0:17:36.350,0:17:41.980 these embryos that have the[br]potential, just like this one 0:17:41.980,0:17:42.680 right here. 0:17:42.680,0:17:46.340 These all have the potential[br]to turn into a human being. 0:17:46.340,0:17:50.730 But most fertility clinics,[br]roughly half of them, they 0:17:50.730,0:17:52.950 either throw these away,[br]they destroy them, they 0:17:52.950,0:17:54.040 allow them to die. 0:17:54.040,0:17:56.690 A lot of these are frozen, but[br]just the process of freezing 0:17:56.690,0:17:59.370 them kills them and then bonding[br]them kills them again, 0:17:59.370,0:18:04.290 so most of these, the process of[br]in-vitro fertilization, for 0:18:04.290,0:18:08.740 every one child that has the[br]potential to develop into a 0:18:08.740,0:18:10.500 full-fledged human being, you're[br]actually destroying 0:18:10.500,0:18:14.730 tens of very viable embryos. 0:18:14.730,0:18:18.550 So at least my take on it is[br]if you're against-- and I 0:18:18.550,0:18:21.750 generally don't want to take a[br]side on this, but if you are 0:18:21.750,0:18:33.320 against research that involves[br]embryonic stem cells because 0:18:33.320,0:18:36.580 of the destruction of embryos,[br]on that same, I guess, 0:18:36.580,0:18:40.630 philosophical ground, you[br]should also be against 0:18:40.630,0:18:47.360 in-vitro fertilization because[br]both of these involve the 0:18:47.360,0:18:49.540 destruction of zygotes. 0:18:49.540,0:18:52.520 I think-- well, I won't talk[br]more about this, because I 0:18:52.520,0:18:54.320 really don't want to take sides,[br]but I want to show that 0:18:54.320,0:18:56.850 there is kind of an equivalence[br]here that's 0:18:56.850,0:19:00.755 completely lost in this debate[br]on whether embryonic stem 0:19:00.755,0:19:02.920 cells should be used because[br]they have a destruction of 0:19:02.920,0:19:04.980 embryos, because you're[br]destroying just as many 0:19:04.980,0:19:08.000 embryos in this-- well, I won't[br]say just as many, but 0:19:08.000,0:19:09.580 you are destroying embryos. 0:19:09.580,0:19:12.720 There's hundreds of thousands of[br]embryos that get destroyed 0:19:12.720,0:19:16.210 and get frozen and obviously[br]destroyed in that process as 0:19:16.210,0:19:19.120 well through this in-vitro[br]fertilization process. 0:19:19.120,0:19:22.010 So anyway, now hopefully you[br]have the tools to kind of 0:19:22.010,0:19:25.140 engage in the debate around stem[br]cells, and you see that 0:19:25.140,0:19:29.870 it all comes from what we[br]learned about meiosis. 0:19:29.870,0:19:33.200 They produce these gametes. 0:19:33.200,0:19:35.790 The male gamete fertilizes[br]a female gamete. 0:19:35.790,0:19:39.510 The zygote happens or gets[br]created and starts splitting 0:19:39.510,0:19:42.490 up the morula, and then it[br]keeps splitting and it 0:19:42.490,0:19:45.730 differentiates into the[br]blastocyst, and then this is 0:19:45.730,0:19:47.230 where the stem cells are. 0:19:47.230,0:19:50.320 So you already know enough[br]science to engage in kind of a 0:19:50.320,0:19:53.770 very heated debate.