Basic biological reality means birth mothers can be certain they’re genetically related to their children (setting aside cases of surrogacy and egg donor in vitro fertilisation).
By contrast, fathers can’t know for sure without a genetic test. This can give rise to misattributed paternity, a situation where a man unknowingly raises a child that isn’t genetically related to him or, if he’s tricked into this situation, paternity fraud.
Messy relationship disputes can sometimes lead men to subject their children to genetic testing. The rise of consumer genetic testing (to find out more about your ancestors or your health), however, means that today more men are also finding out by accident.
Data from paternity testing companies released in the US in 2004 found that around 28 per cent of fathers were biologically unrelated to their children.
But, as the Australian scholar Prof Michael Gilding argued at the time, this is a biased sample because it only involves men who are questioning their paternity. Based on more incidental data derived from genetic and medical research, Gilding argued a more realistic figure was around three per cent.
What about more recent data? A US survey published in 2022 of over 23,000 users of FamilyTreeDNA.com found that seven per cent discovered they had a different biological father than they thought.
A Dutch genetic sampling study from 2017, however, estimated just under one per cent of fathers were unknowingly not genetically related to their children. Similarly, a recent Swedish study of over two million families put the figure at 1.7 per cent and found it was decreasing.
Taken together, these recent figures are far lower than what was claimed earlier in the century, but they do still mean a significant number of men and children are still affected.
This article is an answer to the question (asked by Dave Shaw, via email) 'How many fathers are unknowingly raising children that aren't theirs?'
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