Brookings says it’s about $310k per child for a family with 2 children, without including daycare or higher ed costs [1]. US median lifetime income is roughly $1.65 million [2]. Daycare averages somewhere between $10k-$15k/year per child [3]. In state public school tuition is ~$100k for 4 years [4]. Median sales price of a house is ~$425k [5]. Total cost of that house with mortgage interest and taxes over 30 years is roughly double that.
[1] https://news.ycombinator.com/item?id=33879844 (courtesy u/lotsofpulp)
[2] https://repository.library.georgetown.edu/bitstream/handle/1...
[3] https://www.americanprogress.org/article/understanding-true-...
[4] https://educationdata.org/average-in-state-vs-out-of-state-t...
[5] https://fred.stlouisfed.org/series/MSPUS