一位美国母亲曾从精子银行得到精子使一个男孩诞生。15年后，男孩仅仅利用唾液和互联网就寻找到了为他匿名提供精子的生父。

    据《新科学杂志》11月2日报道，这名男孩寻找生父的过程似乎并不复杂——他把带有自己唾液的药棉送到一家“家族DNA服务”网站进行了DNA测试。在缴纳289美元的费用后，男孩根据测试结果在该网站的数据库找到了与自己有着相似Y染色体的男子。由于Y染色体通过父传子的方式一代代地传递下去，这为男孩寻找父亲提供了关键线索。

    虽然男孩的生父从未将自己的DNA提供给该网站，但在9个月后，孩子就在网站的数据库中，找到了与他有着相似Y染色体的其他两名男子。这两名男子互不相识，但有着相近的姓氏（读音相同，拼写不同）。而从他们与男孩Y染色体的相似程度来说，3人的父亲、祖父或者曾祖父有50％的可能性为同一个人，这也意味着他父亲与两名男子的姓氏相近甚至相同。

    男孩的生母曾告诉过他生父的生日、出生地和学历等，但没有公开生父的名字。当获得生父可能的姓氏后，男孩开始转向另一家网站，在那里他购买了和他生父出生地和生日相同的所有男人的信息。果然，只有惟一一名男性的姓与他生父可能的姓相吻合。在接下来的10天里，这名少年与生父取得了联系。

    向寻找亲人的用户提供基因测试的“牛津祖先网络公司”主席兼牛津大学遗传学专家思克斯说：“15年前，当男孩的父亲捐献出精子后，没有人会知道还会发生这样的事情。这则消息，可能使一些捐赠过精子的男人产生不安，特别是在美国这样一个匿名捐赠精子流行的国家。精子银行总是承诺捐赠者要保守秘密，我想这样的承诺可能从此会被打破了。”

    Using nothing more than a swab of saliva and the internet, a 15-year-old boy has tracked down his anonymous sperm donor father, according to details released today.

    By sending a swab taken from the inside of his cheek for genetic testing, the teenager was able to use genealogy websites to trace his father by looking for men with a matching Y-chromosome, which is passed down the male line.

    The genetic detective work has major implications for men who have donated sperm under condition of anonymity and expect their identity to remain secret for ever. The news is expected to lead to a surge of other donor children attempting to find their genetic fathers, according to experts. But the implications stretch beyond the ethical issues surrounding children hunting for their genetic fathers. The boy's ability to use publicly available genetic tests and internet searches suggests that police forces could do the same and obtain the surnames of potential suspects with DNA samples gathered from crime scenes.

    The boy took the saliva sample late last year and sent it off to an online genealogy DNA-testing service called FamilyTreeDNA.com. For a fee of $289 (?163) the boy had his genetic code available for other members of the site to search. Although the boy's genetic father had never supplied his DNA to the site, after nine months the boy was contacted by two men who were on the database and whose Y-chromosome matched his own.

    The two men did not know each other, but shared a surname, albeit with a different spelling, and the genetic similarity of their Y-chromosomes suggested there was a 50% chance that the two men and the boy shared the same father, grandfather or great-grandfather.

    The surname was the clue the boy needed. His mother had been told his father's date and place of birth and his degree subject, even though his name remained a secret. With the growing pile of information, the boy turned to another internet service, Omnitrace.com, which he used to buy information on everyone born in the same place and on the same date as his father.

    Only one man had the surname he had obtained earlier, and within 10 days the teenager had made contact, amicably, with his genetic father, according to today's issue of New Scientist magazine.

    "This is the first time that I know of it being done," said Bryan Sykes, a geneticist at Oxford University and chairman of OxfordAncestors.com, a company that offers genetic testing for ancestry research. "Fifteen years ago, when the father donated his sperm, nobody in the world could have known this would be possible." The news is likely to be unsettling for men who have donated sperm in countries where anonymity is still commonplace, such as the US.

    "Sperm banks are recruiting donors and promising them anonymity. I don't think that's a valid promise any more," said Wendy Kramer, founder of DonorSiblingRegistry.com, a web-based service that matches donor children with their siblings. Dr Sykes added that his own company was now considering allowing its own databases to be used by children seeking their donor fathers.