Yes, and a while ago they thought they'd be looking at a constitutional crisis as both Akhito's sons only had daughters, but then the younger one's wife had a son. He's a lot younger than Mako and Kako though.
The Japanese court always seems stifling to me - the women, when in Western dress, look like they're from 1910 and then there are the laws against them inheriting the throne too. I pity Masako for having to deal with all that and it's no surprise she had some sort of breakdown. It must've been very hard, especially for a woman as intelligent as she is.