GENES contained in sperm are "detrimental" to a long life, scientists claimed yesterday.
A Japanese team found that mice created by mixing the artificially altered genetic material of two females and without using sperm from a male lived a third longer than those born naturally.
The "all-female" mice also had better immune systems and were smaller and lighter than their natural born counterparts.
The findings provide the first evidence that genes from fathers may have a damaging effect on the life span of mammals.
The team from Tokyo University of Agriculture created 13 "bi-maternal" mice by manipulating their DNA so the genes in young mouse eggs behaved like those in sperm, giving them the ability to fertilise. The altered genetic material was then implanted into the eggs of adult female mice.
One of lead researchers, Professor Tomohiro Kono, said that the male gene known as Rasgrf1 was probably to blame for the shortened life span of the naturally born female control group.
He said: "The study may give an answer to fundamental questions of whether longevity in mammals is controlled by the genome composition of only one or both parents, and, just maybe, why women are at an advantage over men with regard to the lifespan."
The findings were published in the journal Human Reproduction.