Are you saying that people who are sociopaths don't have a mental disorder? I believe there certainly is a gene or at least a statistical pattern of genes that predispose someone to be a sociopath, and an abusive childhood will only enhance the disorder. So I do believe there certainly are circumstances where people who suffer from certain disorders cannot choose their actions. Do you disagree with me here?
It is true that people born with a sexual proclivity towards children do have the ability to determine their own actions. Statistically, only half of people with this proclivity act on that drive in their lifetime (which is pretty surprising considering how strong the human sex drive is). So when you have a child who has this proclivity, you know that there is statistically a 50% chance that he or she will end up molesting a child.
I don't have a problem with people of these proclivities being born either, I just think that it is the right of the parents to choose whether or not they want to endure a lifetime of hardship. I believe the right choice is to carry the pregnancy to term in just about every case. I believe that adoption is always an option and people who are thinking of getting an abortion should strongly consider that option. I don't believe I have a right to force my moral opinion down anyone else's throat.
I am not making a value statement based on the physical or mental viability of the fetus in the case of the third trimester abortion. I am conceding that the situation is fundamentally changed when this knowledge is given to the parents. The parents may not have the financial ability/proper health care plan to raise a disabled child. All fetuses being equal, I am weighing the added hardship of the situation as far as the caregivers of the future child are concerned. I am not saying that a handicapped fetus has less value than a non-handicapped fetus. I hope this is clear.
I could make the same argument that if you support the right to choose in the case that childbirth will end up taking the mother's life, then you are valuing a fetus that does not threaten a mother's life more than a fetus that does threaten a mother's life. But we both know that the value of either fetus has nothing to do with it in this case.