单项选择题

Once they decided to have children, MiShel and Carl Meissner tackled the next big issue: Should they try to have a girl It was no small matter. MiShel’s brother had become blind from a hereditary (遗传的) condition in his early 20s, and the Meissners had learned that the condition is a  (1)  passed from mothers to sons. If they had a boy, he would have a 50 per cent chance of having the condition. A girl would be  (2) .
The British couple’s  (3)  about gender selection led them to Virginia, US where a new sperm (精子)-separation technique, called MicroSort, was under  (4) . When MiShel became pregnant, she gave birth to a daughter. They will try to have a second daughter using the technique later this year.
This is not only a  (5)  effective way to select a child’s gender. It also brings a host of ethical (伦理的) and practical considerations—especially for the majority of families who use the technique for  (6)  reasons.
The clinic offers sex selection for two purposes: to help couples  (7)  passing on a gender linked  (8)  disease and to allow those who already have a child to "balance" their family by having a baby of the opposite sex.
The technology is still  (9) . However, Blauer says the company has an  (10)  success rate: 91 per cent of the women who become pregnant after sorting for a girl are successful, while 76 per cent who sort for a boy and get pregnant are successful.

（1）处填（）。

点击查看答案&解析