What law? I've used this account since gmail started, now they need to know more personal details? Seems if I don't enter it I will be locked out of my phone and all google services.
#2: Do note, they want 'a' birthday. Why would you ever consider giving them a real anything? Online services that 'demand' unnecessary metadata, where you decide to give metadata to continue to use them as opposed to dropping them, *always* get fake metadata.
Years ago the washington post used to demand some unnecessary metadata to read articles. I was a 98 year old from Mongolia one day, a 65 year old Peruvian for the next, and the answers were different, and fake, every time (I'd clear their cookie immediately to trigger another 'ask' for the next time I would click on a link to them).
I can think of the most known Children’s Online Privacy Protection Act (COPPA) and some EU safeguards that prevent you from processing a child's personal data without the guardian consent.
I would also guess that there are content restrictions that might be hard to implement on a Google account and they prefer locking children out of their platform. I do think Facebook and many others applies the same method.
Disclaimer: This is not legal advice