Why do some women still continue the pregnancy when the baby is diagnosed with health issues and or mental challenges

I never understood how certain women still goes on to continue their pregnancies when the doctors clearly tells them the baby will be born with this health challenge or this mental issue or disability etc. some claim they do because they feel “called” to do it whatever that nonsense means. In my opinion I feel women who go on to continue their pregnancies knowing the baby will most likely not live very long or if they do they will be faced with a bunch of hospital visits and medications their whole lives and more challenges I feel women like this are selfish in a way. Why bring a baby into this world knowing that baby doesn’t have a strong chance at life or a normal life. That irks me.