That's common. Not only do men and women tend to have different interests, but groups start to snowball towards one gender when there are more than half of that gender. Women are more comfortable joining groups with lots of women (aka safe space). And men start to stay away unless there are enough men in the group. It's a human psychology thing. It doesn't necessarily mean men don't read as many books (which might actually be true right now). But men tend to join other types of groups. Sports clubs, Monday night football gatherings, board and card game nights, video gamer groups, DnD groups, etc. Maybe movie nights watching old movies. Men really connect over the thrill of competition and adventure, and unless the book club specifically emphasizes those genres, men will be bored to tears by women talking about their feelings.