>>84470193No it isnt. Heterosexual didnt even come to mean "straight" until around the early 1900s.
Cultures like the ancient Egyptians, Macedonians, Spartans, Feudal Japanese, Arab tribes, Norse,Chinese,Roman... and more all didn't have concepts of sexuality like we do.
The gay/straight dichotomy is a modern invention. The closet thing they hand was a general tendency to see receiving anal as lesser due to associates with women , hell most of them didnt even have WORDS for gay or straight.