See that kid? The one standing there watching TV wearing clothes? That kid is definitely alive. He's fully formed, can breathe on his own, isn't sucking the minerals out of his host mother, can talk, run, get a social security number if he's allowed... you know, all that stuff? A single-celled organism can be "alive." But at 1 month gestation a fetus can't live outside the womb, neither can it at 2 mos, 3 mos, 4 mos...
The mother (remember her?), she's the one whose body is working as the incubator. Y'all hate the idea of your taxpayer dollars going toward welfare (but it's ok that a millionaire line his pockets with it). A mother has to carry what eventually becomes 25 lbs + worth of child, fluid, etc. all in her belly and then push all that out a pretty small orifice. Kinda like in alien when the dude rips his way out of the host's chest, well it's not the chest getting ripped open in this case, but a pretty close comparison.
This whole process can kill a woman, at many stages throughout the pregnancy all the way up to the final moment. There's preclampsia (dangerously high blood pressure), rheumatoid arthritis, hematomas, hemorraging that won't stop during childbirth... It's not easy to do this. So who are we to force a woman, let's say a victim of rape or if the fetus is brain-dead, who are we to tell her she has to go through all this if SHE doesn't want to?