Do not be too caught up with the idea that 'becoming gay' = 'choose to be gay'. Things keep on changing throughout one's life span, many of which are beyond the said person's control. Or things that may be within his control, but which consequence is beyond a reasonable foreseeability for him to make a well-informed decision, thus making it anything but a choice. And while we're at it, this not an issue of 'or'. Nature and nurture are never mutually exclusive. I'll let the expert speaks: John J. Ratey, M.D., Harvard Medical School (Source: http://www.enotalone.com/article/6229.html)