Yeah, it's kind of interesting but it's not like some sort of GOTCHA. It's more along the lines of interesting trivia.
As far as I am aware the current idea as to what "makes" a person gay (on the nature side of it) relates to a very early series of hormonal processes which occur early in gestation. If you view it as a relatively common deviation from the norm then the first and last observation sort of supports that. Maybe that's changed since I last read up on it, this is just something I was taught years ago -- I do not stay abreast of the science involving what makes homosexuals homosexual. Primapara are less biologically effective at growing babies. The body has to learn how to do it -- that sort of explains the first. As for the last it could be a combination of social factors (age, health of the mother) which lead to deviation.
But, and I think this is probably obvious, an involved study of gayness starts to wander into uncomfortable territory. There's no gay gene that we can fix, but this sort of study... well, it's very easy to pass a kind of judgement using it which is not the point of the study.