They are both "test tube babies." Eileen Gu's mother says she received sperm from a donor, the storying being it was a former colleague at Harvard. No one has been able to figure out who it could have been - and Chinese netizens have been searching far more aggressively for an answer than any American bloggers have.
Its interesting that in both cases, they chose caucasian for the second parent genes, as mixed children a quite popular in China. Further, in good marxist-materialist, post-modern style - Gu's mother has attempted to optimize every aspect of her child's genes and environment, at every moment of Eileen Gu's life.
With such an attitude, no one should be surprised Gu chose to ski for China, when such large profit was on the table.
Since my ex was Chinese I can tell you.....yes, Halfies are quite popular in China - specifically Caucasian and Asian Halfies. Not in every case of course, but I do not the kids of such a pairing often turn out really beautiful.