We know every kid is different and accomplishes things in their own time, but in general what age is it okay to let your kids use a public bathroom alone?

I've never thought twice about taking my son in the women's public restroom. In my mind he is safe when he is with me. I can't possible go with him into the men's restroom, so I've always made him come with me.

Lately, my son has refused going into the women's restroom because he is embarrassed. He is 7 years old so, I understand why he is embarrassed. However, I am extremely nervous to let him go into a restroom at a park or in a store  by himself. I will be the first to admit that I read to many news stories and live in fear when it comes to the safety of my kids. Is he too young to go into a public bathroom by himself?