A lot of factors come into Japan making less babies.
They are overworked. Japanese have a very strict work oriented culture which lends to a lot of them, male and female, being socially inept to carry out dating.
Women. Women worldwide are working harder and marrying later.
It's too expensive for young couples to have babies even if they want to due to age discrimination (Japanese highly respect the elderly). Younger people make less pay.
Speaking of work, Japan's work centric lifestyle means some of these people get home late every night which gives less time to socialize, date, and especially make babies.
Not to mention, many developed nations like Japan aren't the only ones who are making less babies. It's a problem for a lot of nations, it's just not on the scale of Japan's. But in Japan's case, a lot of the problems are strictly due to Japanese culture.
