Being born homosexual, heterosexual, bisexual and asexual is not a choice, and no one should be derogated for their sexual orientation. Reincarnation involves a transmigration of the soul which has no gender, but baggage in its vortex.
Only in the sense of choosing one's own parents that reincarnation does involve a choice, and only a choice of parents and conditions under which old issues surrounding the soul can be resolved. The soul or Atma cannot move on to fulfil its return to oneness with the Paramatma when it still has baggage, including that of sexuality in its vortex.
The word marriage is not to be confused with homosexual unions. Another word to identify homosexual unions as another kind of marriage must to be created. Both concepts are not the same. One is intended as a means for procreation with a life-long partnership as duty in promoting harmony and experiencing oneness between individuals. The other is intended for life-long, same-sex companionship also as a union for promoting and experiencing oneness between individuals. There is no accident in life with the Creator as the cause of all.