都2020年了，为什么还没有出现男性避孕药？

In the late 1950s, an American biologist named Gregory Pincus began researching how hormones might influence the female reproductive cycle and thus prevent pregnancy. In 1960, the first oral contraceptive was approved by the FDA.

20世纪50年代末，美国生物学家格雷戈里·平卡斯着手研究激素对女性生殖周期的影响，从而避免女性怀孕。1960年，美国食品药物管理局批准了第一款口服避孕药。

Pincus’s work led to one of the most important medical breakthroughs in modern history. Over the past 50 years, various forms of hormonal birth control have become so common they’re known simply as “the pill.” But Pincus didn’t focus only on women. He also hoped to create a similar treatment for males. After minimal research, however, he abandoned the pursuit. 

平卡斯的研究促成了现代历史中最重要的医学突破之一。在过去的50年间，各种激素避孕方式已十分普遍，因而被直接称为“避孕药”。但事实上，平卡斯不仅探索了女性避孕，他同样有意向研发适合男性服用的避孕药。然而，经过少量调查后，他就放弃了这个想法。

To this day, no male birth control product has made it to market. But over the past year, there has been promising early progress on new treatments — including a pill, a gel that’s rubbed onto the skin and an injection that acts as a nonsurgical vasectomy —  that could finally bring the first male contraceptive to the public. If that happens, research suggests a “male pill” could drastically reduce unplanned pregnancies, especially in developing countries.

直到今天，市面上仍看不到任何男性避孕类药品。但在去年，男性避孕药品的研发有了较为理想的新进展：一种口服药丸，一种涂抹在皮肤表面的凝胶和一种可以替代输精管切除术的注射剂——它们都将推动第一款男性避孕药品的面世。研究表明，如果男性避孕药品研发成功，将大幅度减少意外怀孕的情况，在发展中国家效果会尤为明显。

Recent clinical trials of male contraceptives have shown promising results, but experts say it could be another 10 years or more before any of the drugs are made available to the public. 

虽然男性避孕药近期临床试验结果喜人，但专家表示，该药还需至少十年时间才能进入市场。

There are a number of factors that have prevented the creation of male birth control, some of them medical and others societal. 

阻碍男性避孕产品研发的因素很多，既有医学上的技术难题，也有源于社会上的各种压力。

Part of the challenge comes down to simple biology. To interrupt fertility in a female body, a contraceptive needs to prevent a single egg from being fertilized, which can only occur in a limited time window. Males, on the other hand, create 1,500 sperm a second and are fertile at all times. Hormonal treatments in development are designed to limit sperm production by lowering testosterone levels. But the effects need to be calibrated just right. Testosterone levels need to be low enough to create infertility — but they can’t go so low as to cause side effects like decreased libido.

首先是来自生物学上的挑战。女性避孕药的原理是，阻止只在有限时间段内出现的唯一卵子受精。与女性不同的是，男性在一秒内可以产生1500个精子，且这些精子能够一直保持活性。目前的激素避孕试图通过降低睾酮水平控制精子产出，但其效果需要精确校准——睾酮水平低到一定程度才能达到避孕的效果，但是过低则会产生性欲消退等副作用。

Beyond medical reasons, the development of male birth control has been hampered by a lack of interest by the pharmaceutical industry and rules about which side effects are permissible in drugs. A large clinical study in 2016 was halted after men in the trial reported serious side effects, including mood swings, altered libido and acne — issues commonly associated with female birth control. Cultural factors, such as the notion that women are responsible for contraception, and fear that birth control would make men less masculine are also frequently cited as inhibiting research.

除了医学研发方面的阻碍之外，制药产业研发意向较低、药物副作用管控条例不明，同样阻碍着男性避孕药的发展。2016年，一项大型临床研究被迫叫停，因为参与实验的男性出现了包括情绪波动、性欲变化以及痤疮的严重副作用。其实女性避孕过程中也同样面对这些常见副作用。此外，一些社会文化因素也是阻碍研究的，如：认为女性应该负责避孕的观念，认为节育会使男性失去男子气概的担忧等，也经常被认为是阻碍研究的因素。