Not sure this is right. I'm going back the thick end of 30 years here and we had girls playing with us from 7/8/9 and it was fine as girls develop quicker physically. Decent players too. Maybe the Vention was merely a hotbed of female football, well ahead of its time.
When I went to uni we had house football (I played for uni and was like well good) so I was captain and you had to have at least four girls, seven lads on a Sunday morning. Just a laugh really. But I can't play for a laugh, can I. So we're playing one dreary Manchester morning on a haphazardly marked park pitch, the ball comes to a hungover Dan 25 yards out, more or less on the half volley...what are you going to do? You thump it, don't you. And I can thump a ball if nothing else. We're talking Neil Masters levels (I've got the arse to match). Straight in some poor girl's mush. I was fucking mortified by that. Never spoke to her again when I saw her around campus.
I still shudder now at the noise it made.