Mixed race offspring are too genetically dissimilar to either parent for them to donate bone marrow if the child needed it. https://www.sbs.com.au/news/why-mixed-race-minorities-struggle-to-find-life-saving-transplant-matches Anecdotally, I know a hispanic-chinese couple who had an extremely difficult pregnancy that required bedrest and the woman almost died in childbirth. Another couple is both the same european ancestry and the mom climbed mountains and went running during pregnancy and did a natural birth with no painkillers. Coincidence?