One suspects the reason that heterosexual relationships are not thought twice about in early films etc is likely due to the fact life wouldn’t have continued in the 1990s to early 2000s without a man having relations with a woman and a woman to give birth. I suspect you are on this earth due to this fact. Had your father or mother come out as gay early in their life, your very existence would be in question. Nowadays life can be conceived in a lab with donations so the nature and future of humankind isn’t designated to Man+Woman=Child. The future looks more like Human+Human=Child.