I would say that to a very large extent our sexuality is biological. All creatures are sexual creatures, driven to reproduce, watch any nature program and you will of course see that this is a given! To almost all animals, reproduction is the only ultimate motivation for anything.
That being said, I would agree that social pressures does distort WHO we wish to reproduce with. However I can't say that I know to what extent this happens. Various studies have been done, and various papers written, but to me the evidence is, as of yet, inconclusive. So I will agree that social pressure is an issue, but how big of one, i don't know.
__________________
|