The polarity of attraction exists because there are two sexes, and whether or not our predispositions are malleable prior to their appearance is not clear, although I think that when one has not yet reached puberty environmental influence would be very powerful, planting seeds of sexual attraction.  Indeed, where I grew up, adults would commonly ask 3 year-olds who their boyfriend or girlfriend is.

But, to me, given that sex acts are all voluntary and sexual attraction is at least able to be supplement with attraction to the other sex, the real issue is whether our culture should promote one type of sexual attraction and its associated sex acts as "normal" or some other term that doesn't harm those who elect to stick with same-sex attraction.  I don't see that as a compromise of freedom in any sense (there have always been people in the US who have embraced their same-sex attraction).  I see it as any other cultural norm that helps society (particularly its children) prosper.