Can homosexuality be an adaptive behavior?

Before I start, this is not a debate on being gay as a choice or birth in general. This is a discussion on a specific scenario.

 

I was in the “outdoors research center” at the office with a friend was relaying a situation with a relative.

The relative (let’s call her Lisa for simplicity) is a big girl.

She is also young, a minor in fact and she likes boys.

The downside is that her perception, real or not, is that her weight leaves her unattractive to those boys.

In this process of desire and lack of reciprocation she has decided that she is lesbian, bi-sexual at least.

This brought me to wonder if and how often people (I suspect predominantly women) choose by being adaptive to be gay.

While I am supportive of the community, I am not a member so I am quite a bit out of the loop. Perhaps some of our friends may have more insight to share on this.

Do you know people in this situation? (are YOU in a similar situation?)

Do they seem happy in general or does there seem to be a longing to spend their time and intimacy with someone of the opposite gender.

Has anyone seen any studies on this aspect of homosexuality?