Philip (the doctor we saw in the last chapter) will trick the female doctor to give lucia the medicine so she will get back her period. because of it she will become pregnant. the ML will be very worried that it's dangerous for her (since he still does'nt know how it's possible, Philip told him that he had to drink blood or something to get a baby). so he will uncover the truth. When he finds out there's no danger for Lucia, he's really happy and love his daugther very much.
Lucia get very very close to damien, becoming a real mother to him, and damien loves his "sister"
Philip is a crazy bastard

So the ml had a baby with someone from his family is that what you're saying...?
I don't mind spoilers :)