An interesting article in The Guardian over the weekend, regarding the genetic screening of individuals who want to have children. Is this just a continuation of the "designer baby" debate? I don't know.

A start up company in the states is offering a service to genetically screen women and potential sperm donors, creating every possible combination of offspring genetically (theoretically - in a computer!), to figure out whether there is a risk of having a child with a genetic defect.

OK. So we're not exactly picking the child's hair/eye colour, or whether they have cute little freckles or not - its not an aim for the "perfect" (whatever that is) baby.

There are a number of genetic disorders which are incredibly rare in the population at large. Generally, these tend to be recessive - meaning that if you carry a not-properly-functioning copy of this gene, but you also carry a normal copy of this gene (one you inherited from mum and the other from dad), you are fine - your normal functioning copy of the gene is enough to do the job. The problem arises if you then decide to have children with someone who has exactly the same situation as you - there is then a 1 in 4 chance that your offspring will inherit 2 not-properly-functioning copies of this gene. Does this mean they will suffer from the disease? Usually, its not this straightforward. It's rare that usually one gene is involved in a disease - for example at least 20 genes are known to affect your predisposition to breast cancer - knowing which versions of these genes you have is still not enough to make it an exact science. Same goes with diabetes or heart disease - involvement of multiple genes and environmental influences play a part. Its a good indicator, but its not perfect prediction.

For diseases that are rare, less money is spent on research into rarer disorders. That's one advantage for this screening process. Especially in the cases where you've clearly never met the sperm donor and have no idea about their medical family history. The company also mentions extending this service to couples who are looking to have children. Seems only fair... after all, why should those going down the sperm donor route have the genetic advantage (for some reason I have the opening lines of the film GATTACA going round my head..). But what happens if you find your partner is not deemed to be genetically suitable with you? Perhaps we need a new section in online dating profiles which expands on the "wants children" question... ;-)

For all our understanding of genetic predispositions to various diseases, do we really have a good enough understanding of the intricacies of the genome to justify not reproducing with someone because of their DNA profile? And what about mutations that arise spontaneously in the DNA of offspring?*

My view point may be different if I knew about some serious genetic defect lurking recessively in my genome, perhaps through family history and personal experience. And for those individuals who are at risk from such diseases and are concerned about having children suffering from diseases for which the prognosis is severe, I can sympathise and see why this service might be the way forward. Overall, I still feel that we are a long way off before we can truly understand the significance of all the variation in our genomes - even that which suggests you have a higher predisposition to a certain disease. A higher predisposition doesn't necessarily mean you will suffer from the disease. For the sperm donor perspective, I can see why this might be a good idea. I just hope it doesn't become the norm when choosing your life partner and thinking about starting a family... kinda kills the romance slightly! :-)

*a certain amount of mutation arises in offspring - its the basis of variation, and not something to be concerned about. Its only when it arises in the wrong place, like in a gene where it changes the protein made by that gene, that it becomes a problem. Or in some instances, a good thing.