Try as I might, I can't imagine a thing about video games that would make it lean towards one gender or the other (excluding "recent" trends of oversexualization and ultraviolence, etc.). I wonder why it was staked out as "male" even at the very beginning?
I can only find pretty skewed articles about it but it appears that it began as a product marketed at adults and children separately, pong at the bar, pong at home with the kids, etc. Then due to cost, they had to pick a single target audience. Maybe it's just a symptom of the rigid social norms of gender at the time?
I was just a little'n back then. I probably didn't even notice.