I would be willing to take advantage of genetic screening/engineering to overcome sterility and guarantee a child free of genetic diseases under certain conditions.
I believe that sterility can be overcome with genetics without a problem, as long as the genes that are altered due not affect anything else. If scientists know the exact gene to alter for sterility and know for a fact that the gene is also not related to an important gene for another purpose. I mean, I would not do it if the gene for sterility also causes cancer or some other problems that we do not know yet because that is only fixing one problem and creating another one that might be even more dangerous than we know.
One other issue about fixing man's sterility is overpopulation. Many parts of the world are overpopulated as it is, so do we really want to fix sterility issues and add to the world's overpopulation? This is an issue that I think really needs to be looked at before we start messing when everybody's sterility problems.
I believe that when we sterility issues should look at other alternatives of having a child, such as adoption, before deciding on a fixing their own sterility issues. Why make more babies in an overpopulated world when we can adopt unwanted children that are already here?
Altering genes to guarantee a child free of genetic diseases is another story all together. My opinion on this has always been the same. While I know that many people do not want to bring life into the world that has genetic disorders, I believe that we need a diverse gene pool in order for future generations to survive. We need different "types" of people so that specific problems do not affect everyone the same way at the same time. If everyone is negatively affected by this same problem, then everyone might be killed by the same problem the same way.
Think of the gene pool as an investment portfolio. All good investors know that a good investment portfolio needs to be diverse with investments of all different natures. If we have 20 different kinds of investments in our portfolio and an economic problem with the country hits a few types of investments, not all of our investments will be negatively affected in the same manner. While we would lose money on a few of the investments, we have over a dozen other investments that will not lose money and might even make money. A diverse portfolio guarantees that not all of our investments will lose money if a problem arises. The gene pool is the same thing. It is not good to put all of your eggs in the same basket because, if it falls, all of the eggs will crack at the same time.
We must also remember that we really do not understand genetics at this time enough to know that any alterations that we make now will not create negative issues in the future. Positive changes we make to a few people now might lead to negative changes that affect large percentages of the world's population in the future. The world needs to keep this in mind whenever discussing genetic alterations.