Ah, right. She wouldn't have been here long enough to have caught up on modern science yet.

"DNA is sort of like a... blueprint, for life. Everyone is a little different. But..." His voice trailed off as he was distracted by pain for a moment, and then he continued. "But our DNA comes from our parents - half from our mother, half from our father. If you compare the DNA of two people you can tell if they're related."