It seems a large percentage of Japan’s youth are not interested in sex — or rather, in doing what they would have to do, to have a relationship.
Now, I just can’t believe that between 30 and 50 % of the population is ace, so there may be something of a cultural as well as linguistic translation error. I suspect it is likely that they could mean “romance” when they say “sex”. I would have a much easier time understanding such a high percentage of the population is aromantic, than asexual, since romantic drive can be influenced far more by culture than sexual orientation.