Can I build myself a wee house in your backyard? - Mello Act?

[hearthstone]

<b>"Structures under 120 square feet are exempt from Uniform Building Code permits. Under the Mello Act, in California, a secondary house under 640 square feet and housing at least one person over 60 is legal. All people have a right to protect themselves from the elements, so any conflict with the health department might be resolved on a one-on-one basis."
This comes from -
https://www.motherearthnews.com/green-homes/microhouse-zmaz95amztak.aspx?PageId=2

I couldn't find much about this Mello Act--do you know anything about it?

Can I build myself a wee house in your backyard? I am over 60 ...

Thanks, Hearthstone.</b>