Embryonic genetic testing is boosting the success rate of IVF pregnancies. However, the capacity to screen for non-life threatening illnesses and to create babies with specific tissue types or physical attributes also raises difficult ethical issues.
Pre-implantation genetic diagnosis, or PGD, has been available for several years for couples who want to avoid passing on genetic conditions to their babies. PGD allows couples with a family history of conditions such as cystic fibrosis or Down syndrome to screen embryos and implant only those that do not carry the disease-causing genes in the mother's uterus. The test can also detect any chromosomal abnormalities that may affect an embryo's chance of survival once it has been implanted in the uterus.
PGD was developed to detect birth defects or diseases that develop in childhood that reduce the length and quality of life. However in recent years researchers have identified numerous disease-causing genes, allowing doctors to pinpoint the chances of developing a disease such as breast cancer later in life.
An Infertility Treatment Authority symposium on assisted reproductive technology this week discussed the scientific, ethical and legal implications.
Agnes Bankier, director of Genetic Health Services Victoria, which conducts pre-natal testing, said it was unlikely parents would be allowed to use PGD to choose their child's physical characteristics. She could not see infertility regulators allowing such social engineering.
In theory, anything for which you could do a gene test could be screened using PGD. But Prof Bankier could not see it being used to test for traits such as intelligence, sporting prowess or a person's height.
Couples who are at risk of passing on a genetic disease to their child can use PGD to select a healthy, disease-free embryo to be implanted through IVF.
"Couples who know because of their family background that they are at increased risk of having a child with a genetic disease have two choices," Prof Bankier said. "They can go and have a test in pregnancy but that leaves them the difficult choice of what to do if they find the fetus has a condition. "Or they can go down the path of IVF and use PGD to test the embryo before they are implanted and select an embryo that is free of the genetic condition."
PGD can be used for sex selection only if the couple fear passing on a gender-linked condition such as haemophilia. Till date only 20 babies have been created in Victoria using PGD.
However, according to Prof Bankier, it is quite a complex procedure that's taxing on the family in terms of the physical aspects of the program, the emotional strain, costs and the yield.