Here’s my personal bizzare twist on things: I feel it is improtant to distinguish between “life” and “humanity”. Life, to me pretty much comes down to cellular activity and having a nervous system (i.e ability to near instanteneously react to stimuli). Worms, bugs, cows, platypi and later stage human embrios(the ones with a spine) have “Life”. I respect things that are alive, are somewhat aware and try not to inflict damage on them, and If life has to be ended in nedes to be done in a fashion that minimizes the suffering; this applies to salmon, chiken, cow and an aborted fetus.
Humanity is set of characteristics that distiguishes us from most animals. How you define it is a fairly philosophical questions but it has to do with learning. use of tools etc. I feel that even babies are not all that human 'till about month 3-4.
Early stage embrios are really less aware than a blade of grass, don’t have a response mechanism (i.e no pain), so I feel that experimenting on a fully grown lab mouse is far more “inhumane”.