Eugenics has a bad rap. All that talk of selective breeding (or sterilising) of people in order to improve the human stock or purify races is terribly distasteful today – and for good reason. However, I wonder if we’re already bringing a kind of eugenics back with modern day genetic testing. And if so, maybe this, much more temperate, version of eugenics is acceptable, or perhaps even good.
Prenatal testing and embryo testing for hereditary genetic abnormalities and disorders is on the rise. We now have the technology to not only determine whether an embryo or a foetus carries a genetic defect that will result in a life threatening disease or disorder, or even one that will severely compromise standard of living, but we can even screen embryos before they’re implanted through IVF.
Certainly, there are broad grey areas over when and in what circumstances such testing can occur – I’m not about to debate these issues – but I am assuming that such tests, in some form, are likely to continue. And, by continuing, we will further have the ability to screen embryos that carry such disorders.
If, by doing so, we reduce the representation in the human gene pool of genes that cause certain disorders, and we do so willingly, then, in a manner of speaking, we’re engaging in a kind of eugenics. Not the kind that attempts to selectively breed (or genetically engineer) to seek out or enhance certain phenotypic traits, but the kind that ends up reducing the frequency of some undesirable traits. One needn’t even start allowing parents to select traits, like eye colour or height, for this weak form of eugenics to hold.
Put this way, my initial suspicion surrounding eugenics gives way slightly to the prospect that this might even be a good thing. But there are still issues, like that we might be inadvertently reducing our genetic diversity, and this could prove problematic down the track.
There are very few (if any) genes that affect only one thing. Genes code for proteins or RNA, and these proteins and RNA can perform multiple tasks and interact with other proteins or RNA in complex ways. Reducing the frequency of one gene in a population might have unforseen side effects. One need only observe the problems that arise when genetic diversity drops significantly – such as in so-called founder populations – to see the ill effects of a lack of diversity.
Then there’s heterozygosity, such as with sickle-cell anemia. It’s a genetic disorder that is inherited if an individual receives two copies of the mutant haemoglobin gene; if an individual possesses only one, the non-mutant is dominant, so sickle-cell anemia doesn’t develop. Furthermore, heterozygous individuals – those who have a mutant and non-mutant gene – gain some resistance against malaria. Eradicating the mutant gene from the population could have a negative effect in terms of malaria resistance. That said, if homozygotes were screened, that alone wouldn’t remove the mutant gene from the population.
I doubt this will ever be a simple black and white issue. There are likely to be plenty of cases where prenatal testing will reveal some non-inherited genetic abnormality, such as Down syndrome, which is not a heritable disorder (although individuals with Down syndrome can have children – if rarely – and they are more likely to carry the syndrome). And we can employ limits and precautions on how we treat the presence of heritable diseases or disorders – or the presence of genes that might increase the chance of a particular disease or disorder. With some cautious use, we might lower the proportion of genes in the population that cause these problems, but not eradicate them altogether.
I don’t know if you’d call that eugenics – admittedly it is a stretch – but even if it is, with some caution, it might actually be a good thing.