Male fertility declines with age - with even a year making a difference, researchers have warned.
They say that after the age of 41, a man's odds of fathering a child decline rapidly. And after 45, those who haven't started a family and want one should start doing something about it.
The warning comes from a study of IVF patients in which the man's sperm fertilised an egg from a donor.
In the context of the study, the use of donor eggs allowed the researchers to separate out the effect of the man's age from that of the woman's.
The donor eggs all came from young, healthy women and so any differences in pregnancy rate must be due to the sperm.
And the difference was clear, with fertility declining by up to seven per cent with each extra year on a man's age between 41 and 45. After that, it declined even more rapidly.
Researcher Paula, of the Huntington Medicina Reproductiva clinic in Brazil, said: "Age counts. Men have a biological clock too. It is not the same as for women but they can' t wait forever to have children."
"They have to think about having children, especially after 45."







据英国《每日邮报》10月20日报道，研究警示男性的生育力随着年龄的增长而下滑，甚至每年都有较大差别。
研究人员称，男性在41岁之后做父亲的几率会迅速降低。而在45岁以后，那些仍处于单身但还想要组建家庭的男性就应该为此费点功夫了。

该警告来自于针对接受试管受精病人的一项研究。在这些病人体内，男子的精子与受捐的卵子进行了配对。
在这种研究背景下，使用捐赠的卵子可以让研究人员分辨出(受精卵的质量)是受男人年龄影响还是源自女方因素。

卵子捐赠者均为年轻健康的女性，所以任何受孕几率上的差别一定是源于精子。

而差别是明显的。年龄在41-45岁之间，男性的生育力年降7%。超过45岁以后，生育能力的下滑速度更快。
巴西亨廷顿生殖诊所的研究员保拉说 "年龄是有影响的。 男性也有生物钟，不过与女性不同，但这并不意味着他们一辈子都有生育能力。"

"男性，尤其是在过了45岁之后，不得不考虑生孩子的问题。"

• healthy [´helθi] a.健康的 (初中英语单词)
• brazil [brə´zil] n.巴西 (高中英语单词)
• warning [´wɔ:niŋ] n.警告；前兆 a.预告的 (英语四级单词)
• fertility [fə:´tiliti] n.肥沃；多产；繁殖力 (英语六级单词)
• biological [,baiə´lɔdʒikəl] a.生物学(上)的 (英语六级单词)