Defective sperm produces girls

WOMEN DESPERATE to have a daughter should chose a motor mechanic to be the father rather than an accountant, solicitor or office manager. New research has revealed that motor mechanics, farmers and miners are up to 40 per cent more likely to have a daughter than white-collar professionals because over half of their sperm is defective.

"Male occupations with significantly increased incidences of semen defects showed reduced numbers of male children," said Keith Harrison of the Queensland Fertility Group in Brisbane, Australia and co-author of a new study, presented today at the European Society of Human Reproduction and Embryology's annual meeting in Tours, France.

In the study of 969 children scientists looked at the fathers' occupation over a five-year period and established sex ratios for each profession. These were compared with the incidents of sperm defects in over 1,400 infertile couples. It showed that men whose jobs are largely office based have only 25 per cent of defective sperm compared with motor mechanics who had 60 per cent defective sperm. Scientists believe that men with poor sperm are exposed to more potential toxins and noxious chemicals when they are at work. "Offspring sex ratios may provide valuable evidence that certain occupations are at risk of toxin contact", said Mr Harrison.

Sperm counts are particularly depressed among city dwellers because of the high levels of toxins from urban pollution. In London 70 per cent of men who offer themselves for sperm donation are rejected compared with only 40 per cent in Hampshire or West Sussex.

The best sperm in Europe comes from Finland where 90 per cent of men produced high-quality sperm.