As a result it is generally accepted that species should outbreed as much as possible – but did you know there is a cost of outbreeding as well?
“To produce healthy children, you should marry a third or fourth cousin. Farther out, the genetic costs of outbreeding begin to outweigh those of inbreeding. That was what a cohort study found in examining Icelanders born between 1800 and 1964. Fertility was lower if the woman’s husband was either closer in or farther out (Helgason et al. 2008).“
