Pregnant mothers have been warned against taking paracetamol even at recommended doses as it might harm the masculinity of their unborn son.
This is contained in the findings of a new study, published in the scientific journal Reproduction.
It found that paracetamol could also reduce fertility in daughters too.
The researchers found the pills inhibit the development of ‘male behaviour’ in mice by reducing the amount of the ‘masculine’ hormone testosterone in their bodies.
Professor David Mabjerg Kristensen, from the University of Copenhagen in Denmark, said: “We have demonstrated that a reduced level of testosterone means that male characteristics do not develop as they should.
“This also affects sex drive.
“In a trial, mice exposed to paracetamol at the foetal stage were simply unable to copulate in the same way as our control animals.
“Male programming had not been properly established during their fetal development and this could be seen long afterwards in their adult life. It is very worrying.”