Junk and pot hinder 'babymaking'

Men who want to be fathers should lay off the marijuana smoking and fast food, according to new studies.

Two studies presented to a fertility conference suggest that marijuana use and excessive body fat may make it harder for a man’s sperm to complete their upstream swim to fertilise an egg.

A study of 22 college students who were heavy marijuana users suggested their sperm moved too fast too soon and deteriorated before reaching the egg.

The men studied smoked marijuana about twice a day.

Dr Lani Burkman, a researcher at the University of Buffalo, said the effect on the sperm came from marijuana ingredients.

The research also found that the marijuana smokers had only about half as many sperm per volume as men who did not smoke marijuana.

Burkman said it could take four to six months of marijuana abstinence for the sperm characteristics to return to normal.

Burkman said women who smoked marijuana were also vulnerable to lower fertility because marijuana’s ingredients pooled up in the uterine fluids and affected the sperm.

Body fat, too, can be bad for making babies, according to another study presented to the American Society for Reproductive Medicine meeting in San Antonio.

Researchers at a fertility clinic in Atlanta examined 30 sperm samples and found that excess weight could lead to a lower sperm count and a higher number of sperm with damaged DNA.

William Roudebush, one of the researchers, said the effect was most pronounced for obese men, those with a body mass index greater than 30.

Roudebush said his clinic often advised heavier couples with fertility trouble to lose weight before trying an assisted reproduction procedure.