Perhaps the most recognized example of this is the MTHFR test for methylation defects. (nwprc.com)
They found methylation defects on several human genes in the cord blood and placentas of ART embryos, suggesting that a similar effect might be occurring in humans as well. (scientificamerican.com)
(Check out this post about methylation defects and this interview with methylation expert Dr. Ben Lynch for a good primer on Methylation) (wellnessmama.com)