https://medium.com/makingofamillionaire/rich-families-are-ha...
The source in that article doesn't show a complete reversal of the old trend yet but bear in mind that I think the level of privilege of parents compared to non-parents will be systematically underestimated because we're looking at income (which will both be reduced by having children, and I'm guessing being income-oriented correlates negatively with /wanting/ children so they've probably converted their privilege into other forms). They will also on average have all the forms of privilege which makes you an attractive partner with the time to have kids: looks, background of wealth, easy job.
I think we should very clearly distinguish things that benefit primarily children=everyone, and parents=the privileged.
For example, education directly benefits children and society but time off and tax breaks for parents is more of a benefit to them, the already privileged.
Someone will probably post a reply that we "need" children for pensions but that's kind of a misconception. You can run a pension system where each generation puts money into a pot and gets it back later, the truth is just that we've chosen not to. Basically if there's ever a pot of money government will find a way to spend it, so now we have this weird system where instead of each generation's pensions being self-contained they're offset by one generation. It's a political problem and bad choices rather than some rule of nature.