"this baby came out of you but im not 100% sure its yours"
Funny thing - a woman who applied for welfare after her husband left her hadto supply DNA evidence he was actually the father. The results: he was definitely the father, but she wasn’t the mother. Her children were removed from her custody and she was sued for fraud, even though she insisted they were her children.
Turns out, she wasn’t a surrogate or a kidnapper (the two most obvious explanations) - she was a chimera. As an embryo, she fused at a very early stage with her twin, forming one individual. Her ovaries apparently developed from cells that had originally belonged to her vanished twin. Later on more tests showed that while the woman’s skin and hair DNA did not match her childrens, DNA taken from her cervix did.