I do think I get where you're coming from. Not that you're attracted to someone purely based on if they can produce offspring but more whether they look like they could. So a gay man would still be evolutionary programmed to be attracted to a 'fertile' looking man in the same way a straight women would be, and vice versa for lesbian women/straight men. It's the same for most conventionally attractive features have some grounding in evolution- eg in women- big boobs, curvy figure, plump lips etc it all stems from youthful and fertile looking = good mate. It doesn't mean we base our lives around it or that you can't find people outside that attractive, its all theory. I would also say that most (not all) men wouldn't be attracted to a dangerously thin women, that 'beauty' standard is something purely pushed onto women by advertising campaigns, magazines and supermodels in the 90s/00s. In the same way I definitely see how a man taking hormones to 'be' a women would be unattractive from an evolutionary point of view as it's clear they can't bear/produce children and that would be a red flag deep in our lizard brain, but again that doesn't mean no one is attracted to trans people, again it's all personal preference and a load of theory's that are virtually impossible to prove for certain either way.