By Vanessa Chalmers Health Reporter For Mailonline
Published: 14:36 BST, 25 June 2019 | Updated: 14:36 BST, 25 June 2019
Boys have fewer sperm if their fathers smoked cigarettes before they were conceived, a study has found.
Danish researchers, who presented their conclusion at a major fertility conference, analysed semen samples from almost 800 teenagers.
They discovered those whose fathers smoked daily before they were conceived had sperm concentrations around eight per cent lower.
Experts say the findings 'add another brick in the wall' showing the harmful effects of smoking.
Boys have almost 10 per cent less sperm if their fathers smoked cigarettes before they were born, a study in Denmark has found
The dangers of pregnant mothers smoking have long been established.
However, little is known about whether the father's smoking status leading up to and during pregnancy affects the unborn child.
The results were presented at the 35th Annual Meeting of European Society of Human Reproduction and Embryology (ESHRE) in Vienna.
The study was a follow-up analysis of 778 19-year-old young men born to mothers between 1996 and 2002.
Smoking information, including that on the father, was based on reports from the mother at around gestational week 16.
Scientists at Bispebjerg Frederiksberg Hospital, Copenhagen, analysed the semen quality of the young men using criteria from the World