you're making one false assumption here - namely that it's the goal of a herd or tribe to produce as much offspring as possible - that is not the case at all

take ants for example - all the ants you see are female - but they never produce offspring - instead there is only one queen per colony which is born the same as any of the female workers - but is chosen to become a queen and fed a high protein diet and develops into a queen 

WHAT IF homosexuals are like worker ants ?

let's do some math if a girl starts having kids at 13 and stops at 35 she could give birth 30 times and if some of those are twins she could have as many as 40 kids or so.  yet we couldn't have evolved around exponential growth.  we must have some mechanism as a species to control our own population growth to stabilize it given finite resources.

in Calhoun's mouse experiments the mouse population totally collapses with an infinite supply of food - why ?  because the genetic mechanism used to control population malfunctions in an artificial environment.

actually modern cities are deliberately engineered by the elites to recreate Calhoun's mouse utopia conditions in order to trigger rapid depopulation, and it is possible that homosexuals and other deviants are a mechanism by which the nature attempts to stabilize population growth.

yes we have xenoestrogens deliberately added to our environment but homosexuality existed before microplastics.  it would be interesting to see if it existed predominantly in cities.

if we can accept that homosexuality is "natural" then we can accept that trannies are a phenomenon distinct from simply men pretending to be women.

if Ants can have 3 genders - why can't humans ?