That question, on its face, might be the most preposterous you've ever heard. But one has to wonder whether why, in 25 nations, male homosexuality is illegal (sometimes punishable by death) but lesbianism isn't.
I should qualify my previous statement: To my knowledge, none of those countries has a law that specifically legalizes sex between women. Rather, there simply is no law against such relations.
The simple question is, of course: Why?
Given that most of those countries are either in the Caribbean or Africa, and some are ruled (or at least dominated) by religious fundamentalists, my guess it that women are so invisible that the men in charge simply don't think about women doing it with women. Or, as others might suggest, it's their secret vice: They might find men having sex with men repugnant but have their stashes of lesbian porn.
(When I was living in Park Slope, a newsdealer I frequented also sold porn. He told me all of his lesbian porn was purchased by men and women rarely, if ever, bought porn. I always figured that the reason is that most lesbian porn depicts men's notions of what women do.)
In more religious societies were men are seen as vehicles of God's or Allah's or whatever-supreme-being's will, and women are seen as incubators of men (ideally), it's probably considered more important to protect the moral purity of males. In such places, women are seen as evil and thus beyond protection, let alone redemption.
And there are a good many men--including some in this country--who simply believe that it isn't possible for a woman to have sex with another woman. That, of course, means that their notions about sexual relations are completely phallocentric.
I would love to know whether any woman has ever been punished in any of those countries for having sex with another woman. Or, upon discovering that his wife or girlfriend is doing it with her best friend, does a man charged with upholding the law simply watch and enjoy?