They don't have more kids, anymore. Married women have the highest fertility.

And the statistics for fatherless children are dismal, across the board. It's not a death-sentence, but they all suffer from it.
As far as I know (and I've looked!), there are no statistics where fatherless children outperform those raised in the house with their dad. Unless you consider "being more likely to commit suicide or be murdered" as outperforming.

Example:
https://ifstudies.org/blog/life-without-father-less-college-less-work-and-more-prison-for-young-men-growing-up-without-their-biological-father