Why just first trimester?

[Fmr. Gov. NickG]

I would apply a consciousness test.  At what point in a pregnancy is a fetus able to retain memories?  I'm not sure of the answer, but I'm inclined to draw the line there, wherever it is.

For fetuses that are born unconscious (having never been conscious), I guess I wouldn't oppose killing them, but I don't think the law should permit it because I think it would be preferable to establish a time rule that everyone can easily follow without the need for advanced medical opinions as to each individual case.