"The ministry would be a nice start," Percy said. He'd spent enough time reproducing and cataloguing records not to know that things were there, if only you were willing to look. "A child might not have your last name, but you would still show as the father. Get the records from when you started to have sex until now. It might take some time, but it can be done. I actually did a pretty good job at keeping things organized."
He sighed. "Of course, with Umbridge there, who knows what you will need to do to get those records." He suspected that she would make Cass jump through the hoops because of their relationship. "The only other place would be Hogwarts. They have the names of the children too."