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
>