I can admire beauty in either sex, because it is aethetically pleasing to view symmetrical features. However, I find beautiful people are like Ming vases - stunning, but empty. Regardless of how people look, unless there are several layers of person connecting with you, then it can get pretty boring all the way round. Plus, when I read or write, I tend to be more interested in the character, the flaws, their joys and what keeps them awake at night - rather than whether they have a great rack or a six pack.
And my definition of beauty tends to expand to include those I find attractive in other ways. I wasn't terribly keen on men with full beards until I fell for Julian, for example.
And as for one of my other fictional pin-ups, Monsieur the Archdeacon of Josas: while he's tall and dark, with extremely compelling and expressive eyes, his hair is prematurely grey and has receded into his tonsure. Which is kind of unfortunate at only 35. But he can info-dump on alchemy, architectural symbolism and Neo-Platonism to me until the cows come home…