New Delhi: Pregnant? You may want to rethink popping those paracetamol pills as a recent study has suggested that doing so can harm the masculinity of your unborn son.

According to the University Of Copenhagen researchers, testosterone is the primary male sex hormone that helps develop the male body and male programming of the brain.

Paracetamol is the pain-relieving substance found in the pills, actually damages the development of male behaviours.

Researcher David Møbjerg Kristensen said that a reduced level of testosterone at the foetal stage is also significant for the behaviours of adult males.

Kristensen added that a reduced level of testosterone means that male characteristics do not develop as they should. This also affects sex drive.

The findings indicated that in the study, the mice exposed to paracetamol at the foetal stage were simply unable to copulate in the same way as the control animals.

Male programming had not been properly established during their foetal development and this could be seen long afterwards in their adult life.

The team analysed masculine behaviours in mice involving aggressiveness to other male mice, ability to copulate and the need for territorial marking.

The mice reacted significantly more passively than normal for all three parameters. They did not attack other males, they were unable to copulate and behaved more like female mice when it come to urinary territorial marking.

Another researcher Anders Hay-Schmidt explained that the area of the brain that controls sex drive - the sexual dimorphic nucleus - had half as many neurons in the mice that had received paracetamol as the control mice. The inhibition of testosterone also led to a halving of the activity in an area of the brain that is significant for male characteristics