Intriguing thought from EKanne re the preponderance of men instrumentalists vs women singers with a couple of notable exceptions (Eliza & Nancy). I have often wondered the same myself.
It is easy to practise singing whilst working in the home and caring for children. Playing a concertina or melodeon whilst changing nappies, doing the cooking or going shopping is impossible. So if women haven't learnt to play well before children come along, it is unlikely they will have the time until they have grown up.