I don't think you know what natural law means. This is from wikipedia.
It wouldn't matter if 99% of animals and humans were gay.
> Natural law[1] (Latin: ius naturale, lex naturalis) is a philosophical and legal theory that posits the existence of a set of inherent laws derived from nature and universal moral principles, which are discoverable through reason. In ethics, natural law theory[2] asserts that certain rights and moral values are inherent in human nature and can be understood universally, independent of enacted laws or societal norms. In jurisprudence, natural law—sometimes referred to as iusnaturalism[3] or jusnaturalism,[4] but not to be confused with what is called simply naturalism in legal philosophy[5][6]—holds that there are objective legal standards based on morality that underlie and inform the creation, interpretation, and application of human-made laws.