Human beings and animals are a little different.

Animals have breeding seasons, thus the scent is strong to arouse the opposite. The making love process is just for creating the next generation. 

As for human beings, those with sensitive noses, can smell the menstruation  period of opposite sex for the bisexual men. Wondering is there a heterosexual man on earth? 

However, the human beings put on lots of perfume, thus the light smell is covered。 

As we know that, 6 out of 10 men are homosexual, thus the homosexual men can only smell the same sex body smell which makes them interested and aroused.

Scientists only look at the surface but not into the inner self. The researchers might be homosexual people but dare not come out thus the research is not correct. 

Similarly to the gay fingers. We have discovered it. Read here 

https://riverofrainbow.blogspot.com/2025/01/the-wrong-information-of-gay-fingers.html

Here is the true gay fingers. 

Look at the fingers of yours if you are the true homosexual. Have you seen the real heterosexual fingers, both hands.

Here is to say, many homosexual men are side gays. Why there is no side lesbian? It is because lesbian do not have penetration action.

Exploring the Science Behind Homo and Heterosexuality | 

https://www.youtube.com/watch?v=MXkr_9ftX5M

Natural selection predisposes us to heterosexuality and reproduction. A portion of the population thinks this is a choice or a decision. But not only. Since several years science interrogates the roots of sexual orientation, homo and hetero. Have we really a choice? The spectacular advances in research on the human genome, coupled with recent studies on the effects of hormones on behavior, upsets conventional viewpoints on our sexual behaviors, and control of them by our brain. Science has discovered quite recently that biological factors are themselves influenced by the environment, and individual history. This is new and fundamental scientific data. This document brings new light on the diversity of sexual behaviors, which are not specifically human, since some 450 animal species have been identified as being at least partially bisexual. Homosexuality is not the mental illness of yesterday, nor the genetic defect of tomorrow; It is simply a natural variant of one of our basic biological characteristics, our sexual orientation. Documentary: Gay or Straight, is it a choice? Directed by: Thierry Berrod Production: Mona Lisa Productions