Eggs fertilised by body cells, not sperm

Doctors from Monash University in Melbourne, Australia, have developed a technique in which no sperm is required to make an embryo. Designed as a method of getting around male infertility, the technique involves taking any body cell and 'fertilising' an egg with it.

Body cells, however, contain two sets of 23 chromosomes whereas sperm cells only contain one set. Egg cells carry two sets up until sperm penetrates them, when they eject one set. The researchers have found a way to make the egg eject two sets of chromosomes, one from the donor cell, by exposing the egg to chemicals after the body cell is added to it. The chemicals cause the egg to eject the excess chromosomes, leaving the correct number for it to develop as an embryo.

The research has so far only been undertaken in mice, but mouse embryos produced in this way have developed relatively normally, and experiments with implanting the embryos into the wombs of surrogate mice are due to begin soon. In theory the technique might one day be used to help an infertile man father a child even when he has no sperm or his sperm is defective. Currently, couples in which the male is infertile have to rely on donor insemination, but many infertile men desire to have a child that is genetically related to them. Dr Orly Lacham-Kaplan, leader of the research team said that it might also enable lesbian couples to have their own genetic baby, although problems might be encountered by the lack of paternal genes, which control some aspects of development.

The scientists stress that the research is in the earliest stages of development. If offspring can be produced from the mouse embryos, they will be tested to see 'whether they have genetic abnormalities, whether they are capable of reproducing, and if the offspring from those pups will be normal as well', Dr Lacham-Kaplan said.