Imagine that, at some future date, before marriage licenses are granted, couples would have to submit to testing of their genetic profile. If it were found that a certain man and woman who wished to be married both carried defective genes, they would be permitted to marry, but forbidden to have children under penalty of law. Assuming the role of scientist, lawyer, man and woman directly affected by the law, or a taxpaying citizen, discuss the pros and cons of this law based on that perspective.
Marriage is not currently understood as a biological coupling of two people, but as a social coupling of two people. In order to justify the testing mentioned here, marriage would need to be defined only along lines of procreation or potential procreation. The first hurdle, then, would be to change views of what marriage is and what the word "marriage" means.
Many problems exist with the idea in question. Unfortunately, genetic testing does not reveal all problems which can exist for the child of the two parents being tested. If a couple or unborn child were tested for the spina bifida issue and it came back negative, all would be assumed to be well. Unfortunately for the real couple this happened to, their only child was born with osteogenesis imperfecta or brittle bone disease which was not detected and with no family history of the devastating disease, it was not on the list of things to check. So, even if we test using genetic testing, it does not necessarily prevent medical issues happening to children. Genetic testing would not necessarily have revealed the Obsessive Compulsive Disorder with which my son lives either. So, I see no resolution happening to prevent disorders by such a law. Even if it did reveal genetic issues, it should be a couple's decision, not the status of law.
Another problem with this Draconian policy is that a couple, I believe, has a one out of four chance of having a child with the possible condition. So, the policy would be overkill, so to speak, from a scientific point of view. Today, it can be easily ascertained whether or not a fetus has the condition in question, at which point a decision could certainly be made.
I should add that there is presently at least one group of people that tend to submit voluntarily to such testing, the Chasidic Jewish population of New York City. There are many Jewish genetic diseases, and there is a program for testing, since the gene pool of Ashkenezic Jewry is not very large. I would imagine that many African-Americans routinely get tested before marriage for the sickle cell trait, too.
I think this is a bad idea. It seems to imply that the couple should not get together if there is a genetic risk to the child. The couple should know, I suppose, if there is a risk- but there is a slippery slope here. It takes the emphasis from love to procreation, which I do not think is right. It also implies that the couple wants a certain kind of baby.
From the point of view of the couple involved, there seems to be only one good point. It's probably good for them to know of the risks to any children they might have. That way they can be prepared. But they would not like the law at all if they believe that, for example, it is God's will that they have children and, if the children have problems, so be it.