NRK had a series on puberty that is no-nonsense, straight to the point. It was hosted by a physician. Most of it is on YouTube, and from a very brief look has English subtitles. Warning, it contains full frontal nudity of people at various ages. It is rated for children in Norway, but might be shocking to someone not used to seeing nipples on TV. It should be quite informative. Watch it yourself and decide if you want your son to see it. I have no idea if it is geoblocked.

Luckily, I’ve been able to get away with only using Teams for meetings, so my exposure is limited, but last time I messed around in the top right corner there was an area that indicated it would show notifications from other accounts.

I have had no need or desire to test this, though.

Apparently the dumpster fire known as MS Teams supports multiple accounts now.

But you can still buy all the older systems. It’s not like they stopped producing or supporting older standards. Both my local shop and the webshop I use have all cassettes from 7-12 gears. Neither currently has 13 gear cassetes, though.