What in the world are you talking about? You're using your own personal opinion and using it to morally reprimand others. I AM an embryologist and your "science" is massively over simplified.
They believe it's a right of the mother to kill an unique individual in his first stage of development - an individual that she's entirely responsible for their current condition - simply because she wishes to do so.
Unsafe birth, impregnation due to rape, inability to care for the child or the lack of matrurity to go through a9 month pregnancy process. You don't get to decide the circumstances of other humans. Simply because she wishes to do so is over simplification and it's pretty obvious you're looking at it from a biased perspective.
There's no scientific argument about the fact that after conception a distinctive human being starts developing. Embryology is as clear as it can be when it states that a member of the human species come to existence in that beginning, when an unique DNA is formed. I find ludicrous that you guys think a fetus is not human. They're not only human but also with inalienable rights of life and liberty - rights that are intrinsically related to his condition of member of the humanhood.
I'm actually wondering if you truly realize how flimsy this argument is... I'm trying to figure out if you hope I won't notice your own moral skew on it or if you just truly believe this is the only perspective someone can have on it that's reasonable. I digress.
The "humanhood" you're referencing is a deeply debated point. Your own "DNA CONCEPTION = HUMAN" ideal is massively outdated. It was taught in the 60's. The problem is you have very little knowledge of the process you're actually even talking about..
Not everything stemming from fertilization even results in a human. Objects such as hydatidiform moles, choriocarcinomas, and blighted ovums are clearly not. Neither will every normal zygote develop into an adult. There are many fertilized eggs that never implant and are "simply washed away" after conception. Your point is so oversimplified and you can't use "there's no scientific argument" to just ignore your awful, awful generalization.
I'm going to go eat some pho now but I'd consider you research the topic you're so invested in a little bit more carefully. Just because something is "formed" doesn't mean it's instantly a human. It doesn't have a brain, a heart, an identity, anything. You don't have the right to take your moral reasoning and implant it on everyone. The thing you're calling a human is literally just a bundle of cells, is DNA the qualifier? I've already established DNA is and can be shared and not result in a human even after "conception" (you're using that term loosely, btw). Using your line of thinking I can go back as far as DNA in sperm as human due to it's potential to one day (maybe) become a human. Everytime you masturbate you're committing mass genocide. Shame on you.