"I am my daughter's father."
Translation:Io sono il padre di mia figlia.
I almost wrote the same thing until I reread it and realized I must be half awake :). "My daughter's father" does mean "the father of my daughter." Kind of a silly thing for someone to say, but you get a lot of that on DL. Probably not a useful sentence for real life but helps to learn grammar and vocab.
I got this wrong too. As a female, I read it several times as "...my father's daughter" and even after it was marked wrong (grammatically correct, I think, but wrong translation) it took me quite a while to realise I had read the English wrongly. I'm a girl! Why would I want to say I am anyone's father?!?
della = di + la
the article is not needed for singular family members. You can find more this site: