Taiwanese family living in Taiwan and frequent Japan prior to having kids and after having kids.
Most people are quick to point out the gruesome work culture, but honestly, that is just a small part of the total issue.
1- Japanese people culturally hate outsiders. So their immigration system is setup to almost never give a foreigner citizenship.
2- Japanese people culturally have a mindset that if you pop one out, it's you and only you that share that burden. That means that if you're on a train and struggling with a crying toddler that is tired of standing, nobody and I mean nobody will let you have their seat. Half the patrons will turn up their volume on their headset and the other half with mean mug/glare at you for annoying them. You wanna know the worst part. This mindset transcends to the kid's grandparents. That's right. The grandparents will not lift a finger to help you.
3- The government is not making it easy to help the families. Do you have a sleeping kid in a stroller? Well, you better hold the kid if you're using mass transit. Elevators are an afterthought. So once you get off a train, you either have to walk an extreme distance to get to an elevator or in some instances there isn't even an elevator at all. In some rare occasion there is a designated elevator for strollers and wheel chair access, it's jammed packed with people who is able-bodied and can take the escalator, all of which won't exit the elevator to let people with wheel chairs or strollers in.
I went to Osaka Universal studios and ask to rent a stroller. The guy didn't speak English at all. We eventually used my phone to translate and he asked me my kids age. I said 5. He said, is today his birthday? I said no. He turned 5 a few weeks ago. He then poceeds to deny me from renting a stroller. I reasoned with him telling him my kid is having major jet lag and needs a place to sleep right now. He told me to just go back to the hotel to sleep because he wasn't going to rent a stroller to me.
I love Japan and the Japanese people, but honestly they all hate kids.