Checking for genetic disease

Igros Moshe (E.H. 04:010) Checking for genetic disease. Concerning children who are born with short life span’s of only two or three years because of a genetic disease Tay Sachs. It requires that both parent’s have the defective gene, though  this has no effect on the parent’s health. The question is whether to check for this gene before marriage because if only one parent has the defective gene the condition does not appear in the children. The test involves a blood test of the man and woman. If it is found in the test of either then they are careful to marry only someone who doesn’t have the defective gene. I am being asked whether it is proper for a young man or woman to be tested for this? Furthermore if it is good to know, this, should it be done when they are children or only when they are ready to get married and should it be done openly or secretly? After studying the matter and finding that this condition happens to a small number of children and therefore normally one should say Tamim Tihiye - be innocent or trusting with G-d and don’t investigate the future [Rashi]. Nevertheless since the test requires very little effort, we need to ask if the test is not done when it is relevant then it is like closing one’s eyes to avoid seeing what is there and since that if G-d forbid it happens that there is a baby born with this condition which causes very great distress to the parents that therefore it is appropriate for someone looking to get married to be tested? I think that it is obvious that it is necessary to publicize through newspapers and media so that the test is known however the testing should be secret so that no one knows the identity of the person, The doctor doing the test should not reveal the results to anyone because even though scientifically the condition only occurs if both parents have the defective gene, many people will not believe this and the man or woman with the defective gene will not be able to get married. Therefore the whole matter needs to be done secretly and it is also a good idea to test a large group at one time like the entire yeshiva or school. Also since it is well known that people suffer from nerves and they imagine things that are insignificant to be overwhelmingly great especially in America, G-d forbid that this test be done to boys prior to their interest in marriage which for the majority is the age of 20 and it should not be mentioned to them at all. Girls generally should not be tested before the age of 18.