"Not at a micro level. The genetics of the sexual will not be passed along if the sexual maintains a sexual life. Artificial insemination is a mechanism to bridge that gap, however it doesn't mean that gap doesn't exist. Dialysis will bridge the renal function gap but it doesn't negate it because not all renal problems will be addressed, and not all sexual males or females will have the number of offspring that their hetero counterparts will. Because there's likely no genetic component to sexuality outside of development issues, this would not probably not be an evolutionary issue, ergo not a "survival of the species" issue unless the species was narrowed to only sexual people."
The discussion was about whether or not sexuality is unnatural. You'd have to define unnatural first, but if it was something along the lines of "cannot lead to survival of the species and instead would lead to extinction" then sure, if the species is only sexuals. That's true for murders as well. Murder is detrimental to survival at a micro level but it doesn't seem to affect us at a macro level. So you have to define your parameters. The ins ution of sexuality (if there is such a thing) is a macro level affect. sexuals are each micro level, their ability to reproduce isn't hindered but their tendency to do so is. This is the same with animals who, for whatever reason do not mate successfully.