The purpose of sexuality is to reproduce, hence any condition (genetic or other) which directly effects an ability to reproduce according to their physical gender would be a malfunction, and hence aberrant. Why wouldn't it be important to fix that just the same?
The mandate of evolution is not reproduction but the perpetuation of the genome. Reproduction (sexual or otherwise) is one part of this but an equally important part is for a species to not exhaust its resources. Various species have developed a variety of strategies to accomplish this, including varying sex (i. e., male to female) ratios, limiting reproduction to certain "alpha" male and female members of the pack, and perhaps to genetically induce homosexuality into a portion of the population when stressing resources is a more eminent threat than is decimation of the species. The human species does not appear at the present time to be threatened with bottlenecking or annihilation, but there are some early indications that the population density has reach the point where resources are being stressed.