Are people born as homosexuals or it's a social construct?

I saw Ned saying how homosexuality is not probably something one is born with .. And from what I've seen as scientific work about this.. is how homosexuality is multifactorial and to a degree

That's nothing new I guess but there are few elements that are important..  All embryos are XX and only in the 2nd month the embryo may turn into XY (if that was the genetic match that happened)  

This means , in the following months depending on the various factors including how much the mother will produce certain hormones it affects the embryo in many ways .  But it's so complicated . They found out how if the foetus is exposed to extra testosterone in the 4th month the XY will have higher dose of testosterone later in life and even the size of the penis is determined by this . (also that ration of index and ring finger is true)

The british scientist who worked on this for some 10y went on to measure every single athlete he could (for that period of time) their fingers, penises, increase in speed (if they were sprinters etc)  ...But if the foetus is exposed to testosterone in another month of the gestation , then it will have a different effect but also if the foetus is exposed at some stage to too much of estrogen , it will affect the XY later on as well .  It can affct to a point that estrogen will cause them to be inclined to the same sex because they're producing too much of the feminine hormone. (this is when we hear men say how from an early age they preferred boys and they themselves felt a bit girly)

Therefore, some boys definitly are born with homosexuality but for some it'll happen later on in life , for other reasons... Mainly because sexually we're a species that is almost the only one (maybe dolphins are the same) who are having sex for fun and it's not driven by the need to reproduce.