As a matter of fact, I am staunchly in favour of the legality and moral permissibility of early-term abortions; I take sentience or psychology to be the ultimate boundary-marker of moral status. My concern is not with the rights of the foetus, but with a.) the rights of the resultant child to be raised within conditions conducive to its happiness, healthy development, and future autonomy and b.) the rights of any member of society to live in a society in which the conditions of justice are preserved over time. That 'heterofication' might be done to a foetus without rights does not imply that it is morally neutral, as the body of the foetus is the body of the resulting child; what is done to that body is, down the line, done to the child. (Similarly, if I infected your blood-transfusion with AIDS, I would be harming you, though the blood itself has no right not be AIDS-infected.)

Of course I should not get to decide what another parent does with their unborn child: the matter should obviously be decided through adequate political processes (referendum, judicial decision, etc.). However, my point is quite simply that there are, in fact, individuals other than the parents of a child who have a say in what is done to that child. The state (which we may regard as an 'artificial person' for the sake of argument) is the most obvious example, and note that the state's rights as a protector of the interests of children are far-reaching. Here, the requirements of education are the most notable example: every parent has a duty to provide for its child an adequate education, whether by entering it into public schools or by securing some equivalent form of private education. The content of the child's education is subject to somewhat strict controls: you cannot tell your child anything you like and comply with your legal duties as a parent. As a conscientious individual, I also have an opinion on what a child may and may not be taught as part of their education: they may not be told that the Earth is flat, that the Queen of England is a Martian, or that Darwinism is untrue; furthermore, I am in strong favour of civic education.

Passing moral judgement on how others treat their children is not equivalent to tyranny unless it is backed up by coercive intervention, and only then if such coercion is morally unwarranted in light of the manner in which the actions of the parent affect others (including, of course, the child). I do not think that I get to 'decide', as if my moral claims are guided by whim and quirk; as a person of conscience, I draw upon common moral concerns (the welfare of children, the fight against injustice and inequality) in order to motivate an argument for state intervention against individuals attempting to 'cure' their children of morally arbitrary and irrelevant characteristics such as race, sex, and sexuality. I oppose state laxity in the face of such attempts because the rights of homosexuals to participate as equals within society are denied and endangered, and because such attempts constitute new dangers to those rights. Again, see the analogy with the racist society: in such a society, legalising the 'breeding out' of black skin would be part and parcel of a defeat conceded to the powerful cultural forces of injustice.

It is in no sense irrelevant what you or I think of as desirable or a good thing, unless our judgements are born of idiosyncratic concerns that cannot be publically justified against principles acceptable to conscientious and reasonable persons. When we draw upon publicly recognised standards of justice and morality, we are in no sense exercising moral tyranny.