I'm another "by being born".
My mum is and has always been a complete narcissist. She left my dad and I when I was 4 years old for another woman, I saw her once at 16, then when I was 20 she got in touch to show off her new fiancee. Realising dh and I were getting married too she forwarded the date to before ours.
She did come to our wedding, made a HUGE deal out of being the "brides mother", slagged off my dad to everyone (who raised me alone and penniless), then when we saw the wedding video found she had been making faces at me when I thanked the people who helped and handed out gifts (best man was crap so i ended up welcoming the guests etc).
I naively tried to get in contact after the honeymoon, even posted her one of the proffessional wedding pics of the two of us, but she ignored my calls.
Fastforward 10 years and I haven't seen her since, she has never met any of our dc (I have 4), not even when I nearly died with my dc1 and I know she knew through other family.
I don't know why somepeople have children.