[Nayrael]

Spoiler:

Touma's mother is much younger then his dad. She even commented on how Touma, like his father, has a habit of seducing younger girls (in this case, she was talking about Mikoto).
But what scares me about age of Mikoto's mom is the fact she must have been really young when Mikoto was born. She must have been bellow legal age or else she would have ended her university life in these 14 years, even if she wasted few of those years.