Concerns over IVF contamination risk

Gee, your baby looks like my lab experiment
From New Scientist, Dec. 3, 2005, pg. 10 (requires subscription or university access)

SOME children conceived by a common method of IVF (in vitro fertilization) could be carrying chunks of bacterial DNA in their chromosomes, according to a study in mice. The researchers who conducted the work say that such accidental genetic modification would be very rare, but they argue that fertility doctors should take more precautions to exclude it.

Intracytoplasmic sperm injection, or ICSI, is used to help would-be fathers with very low sperm counts or sperm that cannot swim normally. Rather than mixing sperm and eggs in a culture dish as in conventional IVF, technicians take individual sperm and inject them into a woman's eggs. ICSI has been growing in popularity since its debut in 1991, and now accounts for around half of the IVF procedures in many countries, including the UK and the US.

[…] So Pedro Nuno Moreira and his team at INIA, the Spanish agricultural research agency in Madrid, decided to investigate the possibility that children's DNA could be accidentally modified if a sperm sample was contaminated with bacteria. They mixed samples of mouse sperm with Escherichia coli containing a gene that codes for a fluorescent protein, and then used the sperm in ICSI.

For fresh sperm "washed" by spinning in a centrifuge, to separate them from the other components of semen, 12 per cent of newly fertilised embryos contained the fluorescence gene, although it was not found in embryos that implanted in female mice. For samples of sperm that had been frozen but not washed in this way, 19 per cent of newly fertilised embryos and 6 per cent of those that implanted contained the gene (Human Reproduction , vol 20, p 3313).

[…] But Moreira points out that sperm samples are frequently contaminated with skin bacteria carried by the donor. He argues that IVF clinics conform to different standards, and many should take more precautions to eliminate the possibility of accidental genetic modification, such as treating sperm with antibiotics. "It's better to be sure that no children will inherit these problems," he says.

One worry is that bacterial DNA could disrupt genes that suppress cancer. Bonduelle thinks this unlikely, adding that the children in her study seem to be healthy. But she concedes that the consequences of accidental genetic modification might emerge later in life. "It is one more reason to continue the follow-up over a long time," says Bonduelle.

The risks are low, I suspect, but the consequences could potentially be pretty severe. There could also be issues – perhaps worse – with virally contaminated semen. At any rate, it has the makings of a good movie plot.

In vitro fertilization involving a married couple is frowned on by the Catholic church for dissociating reproduction from the marital sex act; it expect that it’s frowned on by ECUSA because it involves a man and a woman (sorry - couldn’t resist).