Ehhh, my issue would be whether the clones were self-aware autonomous beings yet. Which seems to be a more relevant issue rather than their birth state. At least in the case of their artificial gestation cases.
By today's standards in most countries where abortion is legal, the male progenitor has no say in the matter. The only person who can decide it is the woman and that's because she's carrying the baby inside her body. Someone who'd force a woman to abort, by say making her take an aborting pill, would be charged with a felony. This means that Riker had no right to end his clone's life no matter how unfinished the latter might have been.