One stumbling block which always creates static in the lay reporting is the use of the word "choice." It is not a commonly used term for behavioral analysis.
The thing is, either you believe in some form of free will, in which case essentially all behavior is a "choice," or you follow a theory of psychophysiological determinism, in which case you seek environmental conditions which determine behavior, and "choice" is a mere subjective experience, not a cause.
It is useful to understand this by asking yourself, if you are a thorough heterosexual, when was it that you "chose" to be straight rather than gay, or rather than nothing? Odds are, if you are honest, you can't remember ever "choosing" such a thing.
One other complicating factor that renders most discussions useless, is that "homosexual behavior" is a broad category of behaviors that may arise from any of a number of causes. No one who seriously researches behavior thinks there is only one "cause."
There is no psychological determination. People's behavior can not be predicted solely by external factors.
Social scientists can find correlations but never certainty.
Perhaps; but most heterosexuals can remember "choosing" whether to have unmarried sex in a variety of situations, singly or with a member of the opposite sex. Most can remember that for whatever reason, they chose to go ahead when they knew it was wrong, or to resist until or unless it was right, such as being with a person to whom one is thoroughly committed (this latter is admittedly on a sliding scale since the 60s, down from virgin marriage, to a mere agreement between consenting adults).
If a person is not what you call a thorough heterosexual, why would people who populate the clinical observations of the past several decades before gayness has been "cool" reveal their uncertainty unless they had an overwhelming desire to commit social suicide among potential hetero mates? They might discuss sex role anxiety with a counselor, but even if they resolved it to the point of marrying or having children, would not be eager to advertise such doubts. As part of resolving it, they might even create a benign denial or self-forgiveness for having been tempted to transgress due to past abuse, neglect or bullying.
So, can "research" into the labels of sexuality ever be 100% accurate? The pure scientific model cannot escape the issue you raised earlier: the role of free will in self-image and behavior.
After the past 20 years of relentless gay propaganda, it's a certainty that demographers will see a "puzzling" rise in the incidence of "gay identity." It will be a crock; but they will never have lived in a time when society was safe in frowning on unhealthy, disordered behaviors.