A study has shown that Neanderthals took the idea of the close-knit family a little too far.
DNA taken from the 50,000-year-old toe bone of a Neanderthal woman has shown that she was highly inbred.
Experts believe that the inbreeding is the outcome of Neanderthal populations being very small.
Scientific tests revealed that her parents were either half-siblings who shared the same mother, an uncle and niece, an aunt and nephew, or a grandparent and grandchild.
Alternatively, they may have been double first cousins.