How Your Partner's Eggs Make Your Sperm Younger
How the Human Egg Rejuvenates an Aging Sperm
Apr 5, 2009
Medical professionals warn women that if they become pregnant over the age of 36, their baby is at increased risk of chromosomal abnormalities and associated disabilities. If she chooses a career first, before a family, she may find she's left it too late.
Men don't seem to be affected by this problem and are able to father a child all the way through their adult life, even if they are in their 80s or 90s. Doctors didn't previously have any idea why male fertility doesn't have a 'shelf life', like female fertility.
World's Oldest Dad
The world's oldest dad was 90 when he had his 21st child, a girl called Girija Rajkumari. He had 12 sons and nine daughters by four different wives, and as many as 20 grandchildren. He said,
"I want to have more children. If I can survive another few years, I want to have children till I'm 100."
75 year old pensioner, Paul-Louis Mariasusay, from London, became a father again to a baby son. His wife was younger than one of his daughters by his first marriage.
He said: "I may be a pensioner, and it is almost 40 years since I looked after a baby, but I haven't forgotten how to change a nappy and it is just marvellous to be a father again."
So, Why Does Male Fertility Keep on Going and Going?
Each time a cell within the sperm divides, the genetic information at the end of the chromosomes, becomes shorter. The end of the chromosome is called the telomere. These telomeres can be a measure of how old the sperm is, by examining how long or short they are. The cells stop dividing and the sperm will die when the telomeres get too short. This process happens with other cells in the body, too, and not just with sperm.
Now, Professor Tomas Simonsson from the Sahlgrenska Academy in Sweden says that the human egg can extend the telomeres of a sperm cell to make it younger.
"We are the first to show that egg cells have the ability to rejuvenate other cells, and this is an important result for future stem cell research"
Some women have healthy genes, but an abnormality in the structure of their eggs so they are unable to get pregnant. Doctors have recently developed a technique where the infertile woman's healthy nucleus is removed (the middle part of the egg that contains the genetic material) and put into a fertile woman's egg that has had its nucleus removed. As the procedure is so new, they had been worried that the life of transplanted cells might be dependent on the age of the fertile woman's empty egg, but since this discovery, they are no longer concerned.
"The genetic stability of the transplanted cells has been a serious concern up until now, and it was feared that the lifetime of these cells would depend on the age of the cell nucleus that was transferred. Our results suggest that this is not the case", says Tomas Simonsson.
For more information, contact:
Associate Professor Tomas Simonsson, e-mail: tomas.simonsson@gu.se
