I don't have kids, but I do have a multitude of animals (horses, cats, and dogs oh my). From my view, the relationship between the two parents are the "first" child, and we have seen quite a few guys lack the ability and wherewithal to keep up with the relationship or first child, so therefore children after the effect are doomed. As such here is my hit list from the guy view ....
1. Lack of confidence
2. Lack of Emotional IQ
3. Confusion within masculinity in the modern world
4. Fear of the unknown
Society has never empowered or desired or given men the positivity to be a father and parent outside of traditional and religious circles, but the same can also be said for women too.
Not all women are nurturers, but they do have one biological advantage from the start by nature to help kick start the survival of the child (hormones etc)). Men on average only have society to imprint the parenting gene, but it can be seen in some men who have that "spirit".
Our society only desire children specifically male ones at the age of 18 to fight wars, and for both sexes to pay taxes (at a 18). Outside of that it is a toxic stew, for both genders and parents.
So the numbers have been the same, and some might say this is not so great side effect of traditional and patriarchal societies being torn down. Men even when they should not, walk away from the society and their offspring, and some may call it a mental health issues (depression), which pays back horribly upon women and society.