Female embryos more likely to die in pregnancy than males, study claims

Analysis of 140,000 embryos contradicts belief that males are more vulnerable and suggests mortality rate for females is higher overall

Female embryos are more likely to die during pregnancy, scientists have claimed, overturning a long-held belief that males are more vulnerable in the first months of life.

Until now the "fragile male" hypothesis had been widely accepted and it was thought that female babies were more robust and less likely to suffer fatal health problems or genetic abnormalities in the womb.