 |
 |
There is also the strong possibility that frequency of "exposure" as men get older might have a great lot to do with it. Didn't see any factoring in the effect of how often! Seems to me that would be pretty important (or impotent). > ---------- > From: janet paterson[SMTP:[log in to unmask]] > Sent: Tuesday, August 01, 2000 7:30 AM > Subject: NEWS: BBC: Men 'have a biological clock' > > Men 'have a biological clock' > > Tuesday, 1 August, 2000, 00:26 GMT 01:26 UK - The older a man is, the > longer it is likely to take his partner to conceive - irrespective of her > age, researchers have found. > > The odds on conceiving in up to six months of trying decrease by 2% for > every year that the man is over the age of 24, according to a study > published in Human Reproduction. > > The chances of conception within 12 months decrease by 3% for every year. > > In addition, women whose partners are five or more years older than > themselves have less chance of conceiving in under a year of trying than > women whose partners are the same age, or younger. > > The research, by scientists from Bristol and Brunel Universities, is the > first to confirm that the age of a man is an important factor in > conception. > > The findings are based on an analysis of data generated by a long-term > study into pregnancy and childhood. > > The research, being carried out in the Avon area, is known as the Children > of the 90s study. It is designed to evaluate the effects of personal, > social and environmental factors on the development of children from early > pregnancy onwards. > > It focuses on 85% of the pregnancies of couples living in the Avon Health > Authority whose babies were due between 1 April 1991 and 31 December 1992. > > Over 8,500 of the couples who said their pregnancies were planned had > stated the time taken to conceive. > > The researchers used the data to evaluate the effect of men's age on the > time taken to achieve pregnancy. > > Researcher Kate North said: "It is really difficult to quantify the effect > of men's age on fecundity because it is compounded by so many factors. > > "But after adjusting carefully for all the variables we still found that > women with older partners were significantly less likely than women with > younger partners to conceive in under six or 12 months. > > "Because of the size and composition of the study we are confident that > our findings are robust and that the effect is real." > > The study concluded that in a couple who prove ultimately to be fertile, > the probability that it will take more than 12 months to conceive nearly > doubles from around 8% when the man is under 25 to around 15% when he is > over 35. > > Dr Chris Ford, of the University Division of Obstetrics and Gynaecology at > St Michael's Hospital, Bristol, said: "It tells us that to some degree men > as well as women have a biological clock that starts ticking as they get > into their thirties and it also indicates that paternal age is another > factor to be taken into account when doctors are looking at the prognosis > for infertile couples." > > Professor Ian Craft, director of the London Fertility Clinic, said the > impact of male fecundity had not been extensively researched. > > "We assume that men have the same fertilisation capacity from the time > they become fertile, to the time they die, but that is probably not the > case, in fact it is odd to think that men do not experience some > deterioration in their sperm quality with time." > > Professor Craft said it was likely that the number of sperm containing > chromosomal abnormalities increased over time. > > There was also a possibility that lifestyle factors, such as smoking, had > some impact. > > > "http://news.bbc.co.uk/low/english/health/newsid_859000/859675.stm" > > janet paterson > 53 now / 41 dx pd / 37 onset pd / 44 dx cd / 43 onset cd > tel: 613 256 8340 url: "http://www.geocities.com/janet313/" > email: "[log in to unmask]" smail: PO Box 171 Almonte Ontario K0A 1A0 > Canada >