Now whenever someone asks "how did he turn her into this" just link them this chapter. It was partially him, but she already had it in her. She fought it, like her current daughter is now, but she lost to... fate? Genetics?
I'm still a bit insecure about the child. If remember correctly some chapter called it the son and now it's a daughter... And after reading the other comments it looks like I'm not the only one "confused"...
Could be the translator.
I don't remember if the translation ever refer to her gender, but in the artist's Twitter, readers usually call the kid as daughter.