No other possible explanation exists. Atlantic Monthly quoted in Playboy Aug 1993 p. 34. Also Dean Hamer - National Institute of Health, reports that the x Chromosome has a gay gene, so mother is responsible for homosexuality. There is an androgen-receptor gene. The girl will have masculine hearing, which is identifiably different from an unaffected girl's hearing circuitry.
Masculine ears emit fewer hums.
It is known that the homosexual male has brain parts which are more similar to a female brain than a normal male brain. Discovery Magazine - Mar 1994 at 68. The anterior commissure is larger in female and homosexual males. Dr Rich Pillard - Study of 302 hetero males and 302 homosexual males. Later male fetuses may be effected by mother's immune system.