Wasn’t known about? Or they knew it but wouldn’t recognize it?
Seems weird. I can’t believe that any culture wouldn’t know the role of the man. There must be more to it than that.
So, don't believe it. Regardless of your belief, it is true. The pre-Roman Gauls and Celts had the same lack of good family planning information. The unique role of the human female in reproduction is reflected in the Egyptian belief that the pharaoh's successor had to come from the same womb, IOW, descended from the same female line.