没男性也能生育后代 日本培育出人工精子

Scientists have used artificial sperm to restore fertility in a breakthrough that could allow thousands of men to fulfill their dream of fatherhood.

In ‘hugely exciting’ experiments, they have made sperm from scratch, and, for the first time, succeeded in using it to produce healthy young.

Remarkably, the baby mice in the experiments went on to have offspring themselves. The landmark research paves the way for new drugs for infertility, the heartbreaking but little-understood condition that affects one in six couples.

But it also opens a Pandora’s box of ethical dilemmas. Possibilities raised range from men being made ‘redundant’ from the process of creating life, to babies being created through entirely artificial means.

Critics also question whether it is right to meddle with the building blocks of life just to allow couples to satisfy their desire to have children.

Scientists have been trying for years to coax embryonic stem cells – ‘master cells’ widely seen as a repair kit for the body – into turning into sperm. They have had some success but any mice that became pregnant by such means gave birth to unhealthy offspring that quickly died.

Now, Japanese scientists have come up with a series of steps that appear to solve the problem.

They started with stem cells taken from mouse embryos in the first days of life and, using a cocktail of chemicals and vitamins, turned them into sperm in the earliest stages of development. These were then transplanted into the testicles of infertile mice, where they grew into fully-functional sperm.

The ‘artificial sperm’ were then used to fertilise eggs, leading to the birth of 60 ‘grossly healthy’ baby mice, who went on to have families of their own, the journal Cell reports.

The Kyoto University researchers hope to be able to repeat their success using slivers of skin as starting material, allowing men to father children that are genetically their own.

Josephine Quintavalle, of campaign group Comment on Reproductive Ethics, said the work was ‘total narcissism’ and raised the possibility of ‘male eggs’ from men’s skin and ‘female sperm’ from women’s skin.

She added: ‘Who needs men? Who needs women? All that is required now are artificial wombs and we will have completely rewritten human reproduction.’

科学家近日突破性地培育出“人工精子”，可以使不育男性重获生育能力，帮助数千男性实现“父亲梦”。

在激动人心的实验中，科学家从零开始制造精子，而且首次成功地用这些精子培育出了健康的鼠宝宝。

值得注意的是，这些老鼠宝宝还能自己繁殖后代。这项具有里程碑意义的研究为研发新的治疗不育的药物铺平了道路。每六对夫妇中，就有一对遭遇到令人伤心，但原因不明的不育难题。

但该研究也开启了潘多拉魔盒，带来了伦理困境。这可能使男性在生宝宝的过程中成为“多余的人”，也可能使婴儿完全成为“人造宝宝”。

批评者们质疑，为了满足人们为人父母的愿望，就打乱正常的生育过程是否妥当。

多年以来，科学家们一直试图将胚胎干细胞培育成精子。这种主细胞被普遍看做人体的维修工具箱。科学家们取得过一些成果，但通过这种方式受孕的老鼠生出的后代无一健康，不久便夭折。

现在，日本科学家们已经提出一系列措施，这一难题有望解决。

首先，他们取下老鼠胚胎干细胞，使用化学品和维他命混合物，将干细胞培育成早期精子。然后将其植入不育老鼠的睾丸里，它们便会发育为功能健全的精子。

据《细胞》杂志报道，这些“人工精子”随后用于使卵细胞受精，并培育出60个非常健康的老鼠宝宝，它们自己就能传宗接代。

日本京都大学的研究者们希望可以复制他们的成功经验，以皮肤组织为原始材料，让男性拥有自己的亲生孩子。

英国公益组织“生殖伦理学评论”的约瑟芬•昆塔瓦莱却说这项工作“太自恋了”，最后很可能从男性皮肤中提取出“男性卵子”，从女性皮肤中提取出“女性精子”。

她说：“还需要男人和女人吗？现在唯一需要的就是人工子宫，我们将彻底改写人类的生殖史。”