Saw this on CNN last night. An Asian couple having IVF had 2 embryos implanted into the mother. She gave birth to twins that didn't look Asian. She asked for a DNA test and the results were, they were not her babies and also they were not related to each other. Also the clinic didn't know where the mothers embryos are.
https://www.bbc.co.uk/news/world-us-canada-48908133