There is evidence to support the theory that, no matter what physical equipment a fetus is endowed with (determined by XX or XY chromosomes), what determines its sexual orientation is the timing of an infusion of hormones. When and how much. Not unlike a recipe. Oftentimes how a recipe works out depends on when and/or how much of a particular ingredient is added.

This may have to do with the genetic make-up of the mother. And this mis-timing may not happen with every child she bears. Hence, with three sons and a daughter, say, two sons and the daughter are heterosexual and one son is same-sex oriented.

This could also account for identical twins (presumably genetically identical) when one is heterosexual and the other is homosexual. For some reason, one of the fetuses receives the "prescribed" dose of the necessary hormone, and the other does not.

So in examining homosexual males for a "gay gene," researchers may be looking in the wrong place.

Don Firth