How a male contraceptive pill could work | John Amory

翻译人员: Christina Wang 校对人员: Yolanda Zhang

When I tell people

当我跟别人说

that I'm trying to develop a contraceptive pill for men,

我正在尝试研发男性避孕药时，

the response usually varies along gender lines.

对方的反应一般取决于性别。

Women say something like,

女性会说，

"Fantastic. It's about time. When?"

“太好了，是时候了。 什么时候（能研制出来）啊？”

(Laughter)

（笑）

Men have one of two responses.

男性一般会有两种反应。

They either love the idea,

他们要么很喜欢这个想法，

or they look at me a little warily

要么就会用警惕的眼神看着我，

and wonder what exactly I have in store for their testicles.

在想我到底打算 对他们的睾丸做些什么。

(Laughter)

（笑）

So why does the world need a male pill?

那么，这个世界 为什么需要男性避孕药？

Well, what if I told you

如果我告诉你

that of the six million pregnancies annually in the United States,

美国每年六百万的怀孕人口中，

three million of them are unintended?

有三百万都是意外怀孕的？

That's half.

也就是一半。

That's a really surprising number.

这是一个很让人惊讶的数字。

And those three million unintended pregnancies

而这三百万计划之外的怀孕

account for the vast majority of the more than one million abortions

很大程度导致了美国每年

annually performed in the United States.

一百多万次的堕胎。

Happily, the rate of unintended pregnancy has fallen in the last few years

令人欣慰的是，最近一些年 意外怀孕的比例

by about 10 percent.

已下降了 10% 左右。

This is because more women are using effective, long-acting,

这是因为更多的女性 在使用有效、长效、

reversible forms of contraception.

可恢复的避孕方式。

But we still have a long way to go.

但我们还有很长的路要走。

One approach that's finally becoming a real possibility

一种即将成为现实的办法

is better contraceptive options for men.

是针对男性的更好的避孕措施。

Think about it.

想想吧。

We have over a dozen methods of contraception for women:

我们有数十种女性避孕手段：

pills, patches, IUDs, shots, sponges, rings, etc.

避孕药、避孕贴、节育环、 避孕针、避孕海绵、阴道环等等。

For men, we've had the same two options

可对于男性，我们一百多年来

for more than a hundred years:

都只有两种选择：

condoms and vasectomy.

避孕套和输精管结扎术。

Despite having only two options,

尽管只有两种选择，

both of which have significant drawbacks,

且两者都有重大缺陷，

men currently account for 30 percent of all contraceptive use,

在所有使用避孕措施的人群中， 男性目前占了 30%，

with 10 percent of couples relying on vasectomy

其中 10% 的伴侣用的是结扎术，

and 20 percent of couples using condoms.

20% 用的是避孕套。

Why are 20 percent of couples relying on condoms for contraception

为什么 20% 的情侣会 依赖避孕套来避免怀孕，

when condoms have a one-year failure rate of over 15 percent?

尽管避孕套一年内的 失败率超过了 15% ？

It's because many women can't either safely take

这是因为很多女性 要么由于血液凝结等原因，

currently available female contraceptives, for reasons such as blood clots,

无法安全的使用 目前提供的女性避孕措施，

or they can't tolerate the side effects.

要么是因为她们无法承受副作用。

So if we think a male contraceptive would be useful, the next question is:

那么如果我们觉得让男性避孕 会很有效，那下一个问题就是：

How do we go about developing one?

我们该如何研发出 这样一种措施呢？

Well, there's two general approaches.

有两种大体的方向：

The first approach is to try and interfere

第一种办法是尝试干扰

with the way the sperm swim towards or bind to the egg.

精子移动并与卵子结合的方式。

This approach turns out to be really difficult,

事实上这个办法难度相当高，

because it's hard to get enough medication in the small volume of the ejaculate

因为射出的精液容量很小， 很难让足量的药物溶在里面，

and have it still work inside the female reproductive tract.

并且还能在女性的生殖道里工作。

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

这就是为什么更多的研究 集中在第二种方式：

which is turning off sperm production entirely.

即直接停止精子的产生。

This is also challenging.

不过这个方法也很有挑战性。

Why? Turns out that men make a lot of sperm.

为什么？因为你会发现 男性能生产很多精子。

(Laughter)

（笑）

Men make a thousand sperm every second

每秒中，男性可生产出一千个精子，

and to have an effective contraceptive,

所以有效的避孕药

you need to get that level of sperm production

必须把这个精子生产率

down to one percent of its normal value.

降到正常值的1%。

The good news is, this is possible,

好消息是，这是可以做到的，

almost.

几乎可以。

The most studied approach has been to use hormones to suppress sperm production.

被研究最多的方法是 用激素抑制精子生产。

Testosterone and progesterone, when administered together,

睾丸酮和黄体酮， 当一起被服用的时候，

will suppress the signals from the brain to the testes to make sperm,

会抑制大脑发射的 让睾丸生产精子的信号。

and in about 90 percent of men,

在 90% 左右的男性中，

sperm production after three to four months will stop.

这个方法能使精子的产生 在三四个月后停止。

Unfortunately, 10 percent of men don't respond to these hormonal regimens

不过很遗憾，还有 10% 的男性 不会对这些激素疗法做出反应，

for reasons that aren't understood.

原因我们目前还不了解。

For the last several years, my colleagues and I

过去几年里，我和我的同事

have been taking a different approach to male contraceptive development,

采用了另一种解决男性 避孕问题的方法，

one that doesn't involve the administration of hormones.

一个不需要激素疗程的方法。

Specifically, we are looking to block the function of vitamin A in the testes.

具体来说，我们在研究如何 阻止睾丸中维生素A的活动。

Why? Well, for over 90 years it's been known

为什么这么做呢？90 多年来， 我们一直都知道

that you need vitamin A to make sperm.

你需要维生素A来生产精子。

Animals who are deprived of vitamin A in their diet

饮食中缺乏维生素A的动物

stop making sperm

会停止生产精子，

and restart making sperm again when the vitamin A is reintroduced.

当维生素A被重新引进饮食后， 它们又会重新开始精子的生产。

The vitamin A that we ingest

我们摄入的维生素A

is converted by a family of enzymes to something called retinoic acid.

会被一个类别的酶转化成视黄酸。

One of these enzymes is found only in the testes.

其中一种酶只在睾丸才有。

It's this enzyme that we are attempting to block.

我们试图限制的就是这种酶。

The blockade of this enzyme should deprive the testes of retinoic acid

阻断这个酶应该可以 使精子丧失视黄酸，

and stop sperm production

从而停止精子生产，

without affecting vitamin A's functions elsewhere in the body.

同时并不影响维生素A 在身体其他部分的功能。

We're testing this approach in animals

我们正在动物体内测试这个方法，

and hope to move to human testing soon.

希望不久后可以在人体内测试。

Obviously, the impact of such a male contraceptive

当然了，这样的男性避孕药

would go well beyond reproductive biology.

影响的肯定不只是生殖生物学。

It's interesting to speculate about the effect that it would have

它会如何影响男性与女性的关系

on relationships between men and women.

也是个有意思的题目。

One intriguing possibility

一个有趣的可能性

is that a man could monitor his contraceptive status over time.

是男性可以随时监测 自己的避孕状态。

In the last several years,

在过去的几年里，

two groups have introduced home sperm-testing devices

两组人员引入了 家用的精子测量设备，

that are iPhone-based

这些设备基于 iPhone，

and that are easy to use.

并且很容易使用。

A man could test his sperm count and share the result with his partner.

男性可以测量自己的精子数量， 并把结果分享给自己的伴侣。

If the man's sperm count were zero,

如果他的精子量为零，

the man and his partner would feel very comfortable

那他和他的伴侣就可以很安心的

relying on his contraceptive.

依靠他的避孕药避孕。

A tool like this, coupled with a male contraceptive,

像这样的工具，加上男性避孕药，

could greatly increase the role for men in preventing unintended pregnancy.

可以大大增加男性在 预防意外怀孕中的作用。

The researchers who are working on male contraception

研发男性避孕药的研究人员

are trying to create a better future for couples,

正在尝试为伴侣创建更美好的未来，

a future where contraception is no longer considered just "a woman's issue,"

一个避孕不再只是“女性的问题”，

rather an issue for couples to decide together.

而是由伴侣双方一起决定的未来。

So why does the world need a male pill?

所以说，为什么 世界需要男性避孕药？

Well, I believe that a male pill

因为我相信男性避孕药

will help reduce the stubbornly high rates of unintended pregnancy and abortion

可以帮助降低总是居高不下的 意外怀孕和堕胎的比率，

and allow men to equally participate

让男性可以平等的参与避孕。

in contraception.

Thank you.

谢谢！

(Applause)

（掌声）