Because some people may be opposed to the use of IVF and embryo screening in this way. Particually people who feel that life starts at conception. Therefore I don't believe that this policy should be forces on people with genetic illnesses. It should be optional. Also if you are talking about aborting embroys which carry the genetic illness some people may also be opposed to this and again I don't think it should be forced.
YOU CAN KILL A DISABLED BABY AT UP TO 28 WEEKS. In fact a mother needs no reason to kill her baby if doctors believe it to be disabled