User blog comment:B214/Question and Answers 3/@comment-4547267-20140921221703/@comment-24421137-20140921230927

"“More than making children, I want them to become strong kids. A special power in the father’s genes, or otherwise I want greater strength. And that’s where I think that Ise is the most suited one. The power of the legendary Sekiryuutei. Even if the kids don’t inherit the sacred gear, maybe the kids will inherit the aura? This is a good chance"

Right so I think it was just his genes at volume 4