Unnatural sexual Union which must be avoided for giving rise to gay mind in society.Unnatural sexual Union among humans is homosexuality and "woman(prakruti) publicly seeking her man(purusha) WHILE BOTH ARE SLEEPING ON BED EVEN AT THEIR OWN HOME. US govt legalising gay marraiges is just an exigency but is not,has not to be and will not be on permanent basis.That gay law will change soon.

Sex is natural thing to human beings which should not be immoral(ignorant)(knowledge of knowledge to knowledge) by either being celibate or being pervert.
  Nature of sexual union is that man(purusha) gets into sexual union with his own native woman(prakruti).