At the end of the mangá inuyasha and Kagome are shown together,and Kagome shouts "Onii-san!"(which translates to brother, brother-in-law ) at Sesshomaru. So, I'm guessing they got married, but the story ends before any children are revealed.
Where did you hear that he had a daughter? Because he really doesn't have one. You maybe heard from people who made it up! ;) it'd be so cool if he did have kids, though
I think after the final act inuyasha and kagome had a daughter named Inuyamay and koga wanted his son kody to tke her as his wife but she falls in amor with miroku and sango`s boy.
