A new technique that separates male-producing sperm from female-producing sperm based on small differences in the weight of their DNA can greatly increase the likelihood of conceiving a daughter, Virginia scientists said Wednesday. Sperm containing a Y chromosome, which produces males, have about 2.8% less genetic material than sperm containing an X chromosome, which produces females.
Researchers from the Genetics & IVF Institute in Fairfax, Va., report in the September issue of Human Reproduction that they used cell-sorting techniques to isolate sperm containing 85% X chromosomes. A total of 29 pregnancies have been initiated using such sperm, and 92.9% of the embryos are female. Nine patients have so far given birth to 11 healthy girls.
Compiled by Times medical writer Thomas H. Maugh II