Some types of prenatal risk screening are routine in Australia but how far should we take this technology?
Until relatively recently, everything about a baby, including their sex, was a surprise when they were born. Advances in screening technologies mean we can now learn more about a baby while they are still in the womb – but should we?
Prenatal screening for chromosomal abnormalities is now routine in Australia and around the world – the mother gives a blood sample from which foetal DNA can be sequenced. Any abnormalities in the foetal DNA can be identified via this non-invasive prenatal test (NIPT).
Another screening test involves using a foetal DNA sample to generate a polygenic risk score, which is a number that predicts risk of developing certain diseases. This test is illegal to use on foetuses in Australia but available in other countries such as the USA, where some companies who provide IVF treatments offer this screening as part of their service.
Screening for common conditions
Some companies offer to screen embryos against more than 25 common medical conditions, for example, type 1 and type 2 diabetes; breast, prostate, and testicular cancer; malignant melanoma; coronary artery disease; hypercholesterolemia; hypertension; and schizophrenia. They also offer to screen for height, which is not a medical condition, and could be seen as a slippery slope towards selecting for traits such as intelligence.
Professor Peter Visscher, who helped develop the technology underlying polygenic risk scores, has advised caution about the use of these tests on foetuses.
“Where do we draw the line as a society? Will people be wanting to select the smartest embryo next?”
“We need more regulation in this space, and a society-wide conversation around using these technologies to select embryos because of the inherent uncertainty in some of these predictions.
Dealing in uncertainty
“For the genes with a big effect like BRCA 1 and 2 mutations, which increase the risk of developing breast cancer, this technology can be useful for people who have these genes running in their families.
“But for other common complex traits, such as heart disease, with many genes having small effects and much of the risk due to the environment rather than genes, there is so much uncertainty, and that’s without even considering the ethics of selecting for traits such as height and intelligence.”
Potential ethical and social problems
Professor Visscher says companies need to be careful what they are promising, and not mislead consumers about the accuracy of this information.
“Some genetic combinations will inevitably lead to disease, but many won’t. To choose against an embryo because they carry genes that may or may not lead to disease is a much more serious proposition than advising an adult of their risk so they can make lifestyle changes.
“As for screening for other traits, it could potentially create huge ethical, social and maybe even psychological problems, if a child doesn’t match their parents’ expectations.”
