Actually the ideals of an attractive body - in both men and women - have been so different over time that you'd be hard pressed to find any deepset matrix of what straight bio males, lesbians, straight women etc would appreciate. And for most older ages we don't have a lot of firm evidence of what body types women appreciated in men - only what they were supposed to like! Art works and books were mostly created or commissioned by males.
The taste for sun tanned skin and sleek, lithe, muscular bodies is a 20th century thing; in Victorian England - or France at the same time - it was pale skin and for men, rounded, firm bodies, for women fine-boned and slim frames (as you pointed out, Oz). The Romans seem to have appreciated muscular, angular women to judge from statues and coins. And so on. I'm with voxelectronica: even the same person may appreciate quite different things in body shapes, just as in music. Trying to strap it onto biological sex or straight/gay won't work.
And looking for a chemical basis to this isn't useful. It's like saying you could make a robot appreciate Beethoven's Eroica if you run the right chemical reactioins through it.
By the way, if we're talking of subconscious appreciation of the junk that is useful for bedding and procreation, the other day I asked a lady I trust a lot on this forum if she felt that women in general see cocks as objects of beauty or if their eyes are drawn to the crotch of a dressed man to try to figure out "has he got a big hard one down there?" Both men and women have that kind of "art appreciation" for nice breast shapes, even under a sweater, and even when they are not dreaming of getting intimate with the woman (so it's "appreciation without selfish interest") The answer I got was a firm no, she felt nipples (on men) were a lot sexier, and didn't see women spying out the aesthetic shape of dicks on strangers or in movies.![]()