Sunlight does not provide enough UVB for sufficient vitamin D production above a surprisingly low latitude (35N) during the winter months.
https://www.nytimes.com/2018/02/16/well/live/do-i-get-enough...
https://www.nytimes.com/2018/02/16/well/live/do-i-get-enough...
I think a big part of my point was about the resiliency of children. It's worrying that new parents are scared to experience the world with their children.