http://www.mangago.zone/read-manga/hachi_ichi/mh/c010/7/ WOW NO THANK YOU. I WORK HARD S...

Of course, but in the end you will die and your stuff will rot. As you get older, this reality will become increasingly apparent, and your biological clock will make you yearn more and more for children. It's a very natural and powerful instinct.

Will you want to have a child with just anyone, or the best possible person you can attract? You can't just think of yourself if you consider the long-term welfare of your future children. This is part of what Nana was talking about. It sounds calculating, but that's survival. Reality is cold and uncaring. Ideals will only last as long as you have luxuries.