0:00:00.760,0:00:02.160
When I tell people

0:00:02.200,0:00:06.936
that I'm trying to develop[br]a contraceptive pill for men,

0:00:06.960,0:00:10.680
the response usually varies[br]along gender lines.

0:00:11.200,0:00:12.976
Women say something like,

0:00:13.000,0:00:16.296
"Fantastic. It's about time. When?"

0:00:16.320,0:00:17.616
(Laughter)

0:00:17.640,0:00:19.736
Men have one of two responses.

0:00:19.760,0:00:21.976
They either love the idea,

0:00:22.000,0:00:24.056
or they look at me a little warily

0:00:24.080,0:00:27.576
and wonder what exactly[br]I have in store for their testicles.

0:00:27.600,0:00:30.336
(Laughter)

0:00:30.360,0:00:34.200
So why does the world need a male pill?

0:00:35.320,0:00:36.976
Well, what if I told you

0:00:37.000,0:00:41.416
that of the six million pregnancies[br]annually in the United States,

0:00:41.440,0:00:44.336
three million of them are unintended?

0:00:44.360,0:00:45.936
That's half.

0:00:45.960,0:00:48.136
That's a really surprising number

0:00:48.160,0:00:50.736
and those three million[br]unintended pregnancies

0:00:50.760,0:00:54.016
account for the vast majority[br]of the more than one million abortions

0:00:54.040,0:00:56.320
annually performed in the United States.

0:00:57.440,0:01:01.856
Happily, the rate of unintended pregnancy[br]has fallen in the last few years

0:01:01.880,0:01:03.696
by about 10 percent.

0:01:03.720,0:01:06.656
This is because more women[br]are using effective, long-acting,

0:01:06.680,0:01:08.600
reversible forms of contraception.

0:01:09.600,0:01:11.840
But we still have a long way to go.

0:01:13.040,0:01:16.216
One approach that's finally[br]becoming a real possibility

0:01:16.240,0:01:19.360
is better contraceptive options for men.

0:01:20.600,0:01:21.816
Think about it.

0:01:21.840,0:01:25.496
We have over a dozen methods[br]of contraception for women:

0:01:25.520,0:01:31.360
pills, patches, IUDs,[br]shots, sponges, rings, etc.

0:01:32.200,0:01:36.136
For men, we've had the same two options

0:01:36.160,0:01:37.616
for more than a hundred years:

0:01:37.640,0:01:39.240
condoms and vasectomy.

0:01:40.520,0:01:42.656
Despite having only two options,

0:01:42.680,0:01:45.456
both of which have significant drawbacks,

0:01:45.480,0:01:50.056
men currently account[br]for 30 percent of all contraceptive use,

0:01:50.080,0:01:52.736
with 10 percent of couples[br]relying on vasectomy

0:01:52.760,0:01:55.240
and 20 percent of couples using condoms.

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Why are 20 percent of couples[br]relying on condoms for contraception

0:02:01.680,0:02:05.080
when condoms have a one-year[br]failure rate of over 15 percent?

0:02:05.880,0:02:09.056
It's because many women[br]can't either safely take

0:02:09.080,0:02:12.816
currently available female contraceptives[br]for reasons such as blood clots,

0:02:12.840,0:02:15.200
or they can't tolerate the side effects.

0:02:16.280,0:02:20.136
So if we think a male contraceptive[br]would be useful, the next question is,

0:02:20.160,0:02:22.200
how do we go about developing one?

0:02:23.080,0:02:24.920
Well, there's two general approaches.

0:02:25.560,0:02:27.616
The first approach is to try and interfere

0:02:27.640,0:02:31.120
with the way the sperm[br]swim towards or bind to the egg.

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This approach turns out[br]to be really difficult,

0:02:35.080,0:02:39.176
because it's hard to get enough medication[br]in the small volume of the ejaculate

0:02:39.200,0:02:42.520
and have it still work inside[br]the female reproductive tract.

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This is why there's been a lot more work[br]done on the second approach,

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which is turning off[br]sperm production entirely.

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This is also challenging.

0:02:53.160,0:02:57.256
Why? Turns out[br]that men make a lot of sperm.

0:02:57.280,0:02:58.696
(Laughter)

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Men make a thousand sperm every second

0:03:03.680,0:03:05.576
and to have an effective contraceptive,

0:03:05.600,0:03:07.776
you need to get that level[br]of sperm production

0:03:07.800,0:03:10.000
down to one percent of its normal value.

0:03:11.400,0:03:14.336
The good news is, this is possible,

0:03:14.360,0:03:15.776
almost.

0:03:15.800,0:03:20.800
The most studied approach has been to use[br]hormones to suppress sperm production.

0:03:21.760,0:03:25.136
Testosterone and progesterone,[br]when administered together,

0:03:25.160,0:03:29.336
will suppress the signals from the brain[br]to the testes to make sperm,

0:03:29.360,0:03:31.496
and in about 90 percent of men,

0:03:31.520,0:03:34.880
sperm production after[br]three to four months will stop.

0:03:35.680,0:03:39.376
Unfortunately, 10 percent of men[br]don't respond to these hormonal regimens

0:03:39.400,0:03:41.080
for reasons that aren't understood.

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For the last several years,[br]my colleagues and I

0:03:45.040,0:03:48.576
have been taking a different approach[br]to male contraceptive development,

0:03:48.600,0:03:51.320
one that doesn't involve[br]the administration of hormones.

0:03:52.240,0:03:56.520
Specifically, we are looking to block[br]the function of vitamin A in the testes.

0:03:57.360,0:04:00.896
Why? Well, for over 90 years[br]it's been known

0:04:00.920,0:04:03.280
that you need vitamin A to make sperm.

0:04:03.960,0:04:06.976
Animals who are deprived[br]of vitamin A in their diet

0:04:07.000,0:04:08.896
stop making sperm

0:04:08.920,0:04:12.600
and restart making sperm again[br]when the vitamin A is reintroduced.

0:04:13.720,0:04:16.255
The vitamin A that we ingest

0:04:16.279,0:04:20.360
is converted by a family of enzymes[br]to something called retinoic acid.

0:04:21.959,0:04:25.056
One of these enzymes[br]is found only in the testes.

0:04:25.080,0:04:28.176
It's this enzyme[br]that we are attempting to block.

0:04:28.200,0:04:32.616
The blockade of this enzyme[br]should deprive the testes of retinoic acid

0:04:32.640,0:04:34.576
and stop sperm production

0:04:34.600,0:04:37.800
without affecting vitamin A's functions[br]elsewhere in the body.

0:04:38.720,0:04:40.616
We're testing this approach in animals

0:04:40.640,0:04:43.800
and hope to move to human testing soon.

0:04:45.000,0:04:48.376
Obviously, the impact[br]of such a male contraceptive

0:04:48.400,0:04:50.800
would go well beyond reproductive biology.

0:04:51.440,0:04:54.496
It's interesting to speculate[br]about the effect that it would have

0:04:54.520,0:04:56.400
on relationships between men and women.

0:04:57.320,0:04:58.776
One intriguing possibility

0:04:58.800,0:05:03.040
is that a man could monitor[br]his contraceptive status over time.

0:05:03.720,0:05:05.296
In the last several years,

0:05:05.320,0:05:09.576
two groups have introduced[br]home sperm-testing devices

0:05:09.600,0:05:11.096
that are iPhone-based

0:05:11.120,0:05:12.760
and that are easy to use.

0:05:13.680,0:05:17.936
A man could test his sperm count[br]and share the result with his partner.

0:05:17.960,0:05:19.776
If the man's sperm count were zero,

0:05:19.800,0:05:22.616
the man and his partner[br]would feel very comfortable

0:05:22.640,0:05:25.496
relying on his contraceptive.

0:05:25.520,0:05:28.696
A tool like this,[br]coupled with a male contraceptive,

0:05:28.720,0:05:33.040
could greatly increase the role for men[br]in preventing unintended pregnancy.

0:05:34.840,0:05:37.616
The researchers who are working[br]on male contraception

0:05:37.640,0:05:40.456
are trying to create[br]a better future for couples,

0:05:40.480,0:05:45.016
a future where contraception is no longer[br]considered just "a woman's issue,"

0:05:45.040,0:05:47.960
rather an issue[br]for couples to decide together.

0:05:49.320,0:05:51.760
So why does the world need a male pill?

0:05:52.520,0:05:54.256
Well, I believe that a male pill

0:05:54.280,0:06:00.096
will help reduce the stubbornly high[br]rates of unintended pregnancy and abortion

0:06:00.120,0:06:03.016
and allow men to equally participate

0:06:03.040,0:06:04.240
in contraception.

0:06:05.040,0:06:06.256
Thank you.

0:06:06.280,0:06:10.520
(Applause)