Twenty years ago, men and women had similar attitudes towards children - young women, on average, wanted slightly more children than young men, but the differences were nothing to speak of.
Now, on the other hand....
I'm not going to commit sociology here - I don't have time to do a serious analysis of what's behind the drop in young men's fertility intentions. Just two observations:
Children are expensive and, as described in my last post, the real incomes of single men have been gradually falling over time.
The internet (and just about every product Apple has ever manufactured) make it good to be alone.