"To the dismay of gay-rights activists, the Food and Drug Administration is about to implement new rules recommending that any man who has engaged in homosexual sex in the previous five years be barred from serving as an anonymous sperm donor. The FDA has rejected calls to scrap the provision, insisting that gay men collectively pose a higher-than-average risk of carrying the AIDS virus. Critics accuse the FDA of stigmatizing all gay men rather than adopting a screening process that focuses on high-risk sexual behavior by any would-be donor, gay or straight.