A new study has found that women who smoke during pregnancy are more than likely going to give birth to sons who will have a low sperm count.

The research was released as part of a new study highlighted at the annual meeting of the European Society of Human Reproduction and Embryology (ESHRE) in London. It was based on the Western Australian Pregnancy Cohort which began back in 1989 where they enrolled 2,900 mothers-to-be. 

Their sons had a regular assessment before and after birth and when the boys reached the age of 20 - 22, they took part in a testicular assessment which took a look at their semen quality, testicular volume and hormone production.

The results from the study showed that about one in six of the men had sperm parameters that were seen to be below the "normal" threshold defined by the World Health Organization (WHO). They also found that children being exposed to mothers smoking was linked with a lower sperm production.

"The main message from our study is that to reach adulthood with the best possible testicular function a man should not be exposed to his mother's smoking, should have good foetal growth and, in childhood and through adolescence, should be "appropriately grown" - that is, neither underweight nor overweight, and as an adult should not smoke or take drugs" said Professor Roger Hart of Reproductive Medicine at the University of Western Australia.

The professor continued;”The extent of the risk posed by environmental endocrine disrupters is still unclear, but some researchers do attribute the perceived decline in sperm counts to these chemicals within the environment."

"We do not have any evidence to suggest such a link in our study, but we do intend to measure the foetal exposure to endocrine disrupting chemicals from maternal blood that was stored in 1990, prior to the study recruits' birth, and to relate these chemical exposures to the men's semen counts in 2012-3."