There is no sex on the front page of Yahoo at all. You basically don't see any ads or words related to sex. This is pretty much the standard for all major US portals.
But the Chinese Yahoo (or other Chinese portal sites) is totally a different animal.The following picture is the top part of the front page of Chinese Yahoo on Oct. 31, 2005. All the pink-marked sections are related to sex. Here are some of the titles (mostly ads): "Two Sexes", "Male and Female Valuable Book, the Final Station of Sexual Happiness", "Happy Contraception, Making Love at Ease", "Nuclear Weapon of Sexual Happiness for Men".