There's nothing wrong with choosing to have a family and raising kids, but that is a choice. No matter what conditions are set, the person who makes the necessary tradeoffs is going to be in a better position to succeed and YC as a business entity can do nothing to level the field for people who are willing to go all-in versus people who prioritize a comfortable home life.
Again, startups are privilege that form out of the security of societal infrastructure and excess of wealth. Nowhere in society is it prescribed that everyone should be able to forego having a job and drain their savings to gamble at a chance at massive wealth. How is it reasonable that we've come to expect this as some sort of entitlement?
The top comment makes a dismissive remark about "rich white men," and YC being against inclusivity and diversity. The natural response to this is that YC is not racially exclusive, but that they exclude based on those who can assume risk. Yes, but white people are rich so they can consume risk and black people are poor, therefore YC is in reality discriminative against blacks. The simplification of this kind of argument and its decontextualization from reality should be self-evident. Unfortunately, it's emblematic of the kind of emotionally reflexive and broadly appealing arguments we see thrown around instead of practicing any form of intellectual sophistication or nuance. It's far easier to make a glib side-remark suggestive of racial privilege. It's even easier when this is politically and socially trendy, even expected, and the individual making the remarks is protected from backlash by the insulation of a particular ideology.