Gender Engineering
Draws Criticism From Researchers
By Dale Hopper
Associated Press
FAIRFAX, Va. (AP) -- Fertility researchers say they are successfully helping prospective parents fulfill their dreams in selecting whether to have a baby Michelle or a baby Michael.
The technique involves identifying and separating sperm cells that carry the Y chromosome, which produces males, from those that carry the female-producing X chromosome.
Dr. Edward Fugger of the Genetics & IVF Institute said Wednesday that sperm cells can be segregated by the amount of DNA they contain before being used to fertilize an egg through artificial insemination.
The institute's research is published in the September edition of the journal Human Reproduction.
The Y-chromosome sperm has about 2.8 percent less genetic material than sperm with the X chromosome.
Researchers were able to sift sperm to produce samples in which 85 percent of the cells had an X chromosome. If they targeted Y-bearing sperm, the result was a sperm sample in which 65 percent of the cells contained a Y chromosome, The New York Times reported Wednesday.
The institute said 29 women who wanted to have girls became pregnant. So far, nine of those women have given birth to 11 healthy baby girls, including two sets of twins, the institute said. The oldest girl is 2 1/2 years old.
One of the women still pregnant is carrying a boy, Fugger said.
A study of couples wanting boys produced results consistent with what the sperm sorting would predict, Fugger said. Exact results were not released.
Dr. Jamie Grifo, director of reproductive endocrinology at New York University Medical School, is apprehensive about the way the institute is using the sperm-sorting method.
Grifo has been using an entirely different technique to choose the gender of an embryo since 1992 and said NYU applies the technology only to prevent gender-based diseases such as hemophilia and Duchenne muscular dystrophy, which only appear in males.
"They're doing very important research but it's a matter of what they're using it for that worries me," Grifo said. "I don't think we should be doing sex selection."
Fugger said the institute's technique can be used to prevent gender-based disease and was unapologetic about giving families the option of choosing their child's gender.
"It tends to balance sex ratios in families," Fugger said. "There shouldn't be an ethical issue with skewing ratios or anything like that."
Another outside observer, Dr. Robert Stillman, medical director of Shady Grove Fertility Centers, in Washington, D.C., said the institute's research sample is too small to declare success.
"It's really a series of anecdotes," said Stillman, a board member of the American Society for Reproductive Medicine. "A bigger study might put this in the wastebasket where many other attempts at sex selection have gone."
The institute's researchers refined techniques developed for sorting the sperm of farm animals. Fugger said that of the more than 400 animals in five different species born through sperm sifting, none was born with defects.
The technique involves staining sperm cells' DNA with a fluorescent dye and then shining laser light on the cells to make the dye glow. The amount of fluorescent light produced indicates the amount of DNA present in each cell.
Dr. Barry Zirkin of Johns Hopkins University told the Times he was not convinced about the safety of using laser light. And like Grifo, he also questioned the ethical implications of tinkering with sperm.
When it comes to sex selection, he said, "most people feel this is tampering with nature."