98% of all adoptions in Japan are of male adults so that family businesses can remain within the family.
In Japan, 98% of adoptions are actually adult men, aged between 20-30 years old — not children. That is according to government data cited by economist Steven Levitt and journalist Stephen J. Dubner in their book “Freakonomics,” as well as a number of other reputable media outlets also citing government data.
Another reason behind the number of adult adoptions is that they can be used to save on inheritance tax.