Nobel Winner: "Abort Gays"

One of the discoverers of the structure of DNA and Nobel prize winner James Watson (pictured) said a little while ago that if a gene for homosexuality were discovered, a woman should be free to abort a fetus that carried it. There are at least two issues here, if in the future the technology and the knowledge brings us to such a place. Firstly- is it ethical for parents to be able to have complete freedom to choose their child's genetic inheritance (to the extent that technology allows) Secondly- if not, should it be the role of the state to forbid such actions?
To begin I will say that I think genetic enhancement of fetuses is morally defensible. I would argue in a similar fashion to Singer  and say that genetic enhancement is an extension of what we currently consider good parenting; parenting that works to maximise a child’s abilities and opportunities for life in much the same way that good education and nutrition do. Controversial of course, but if one accepts genetic enhancement and selection processes as a valid thing for parents, does that mean Watson is right? Well I would say 'yes' and 'no'.  In the abortion or modification of a homosexual fetus to a heterosexual fetus there is no one who is harmed, unless you think a fetus is a person, which I do not. As such it is not unethical by virtue of harming an individual person. What I believe makes such an act unethical is the denigration of sexualities that are of equal moral worth. Unlike the abortion of disabled fetuses as currently practiced on quality of life considerations (and by extension permits their modification if we had the technology) aborting homosexual fetuses would be based solely on the perceived moral worth of homosexuality, i.e. it is of less moral worth than heterosexuality. 
But where does that leave us? Should the state intervene? This is Watsons' point I suppose; there are many things that we believe are unethical yet the state does not intervene. A liberal point of view. When a person is harmed we can see a strong reason for state intervention. But in this instance it seems that while it is unethical to abort homosexual fetuses, it does not warrant state intervention to prevent it. I base this on considerations of consequences. No one individual is directly harmed. In addition, what if it was illegal? Should the state force people to have gay babies? Would it be in the child's best interests to be brought into the world by a family that held such views of homosexuality? As such it would seem to me that while it is definitely immoral to make moral judgments on the value of people via reference to their sexuality and to abort/genetically modify fetuses on such a basis, the state should not prevent it from happening. And that is where Watson and I agree.