VS Decreasing Population

In Japan, 20% of the gross population became the people over 60 yeras old recently. I am happy to hear that because it means Japan becomes more and more a long-life-time country.
But, many people seem to think that is not good. Because it becomes more difficult for the government to keep our pension system and other infrastructures. Actually, now Japanese birth rate is under 1.25. The number of young generation is decreasing.

We discussed about the topic in our English class today.
We know the main reason of decreasing birth rate is from the increasing unmarried women. Especially the number of 26-30 years old unmarried women is increasing.
Comparing the present with the past, the number of children a married woman has is same.
The couple without children is not increasing.

We didn't discuss so much what we can do to solve this problem. It's a big and difficult theme. Alternatively we talked about marridge.
"Women change after marridge." is the married men's idea.
I can't judge whether that's true or not, because I am a single, but two women students disagreed with the idea. Maybe, depending on the viewpoint, the idea can be both true and unture.

"Before marridge, Men hope Women will not change in the future. But, Women change after marridge." Onthe other hand, "Before marridge, Women hope Men will change in the future. But, Men will not change."
I can't judge this idea again, but it sounds true. A Japanese recent pop-song says a same kind of idea.
" I (man) want a unchanging relationship with you, but you (women) want a stimulating relationship with me." Mmm, I might see.