The laws vary, but they all give exception to people that are roughly 3 years apart or less.

The age of consent in the US generally varies by gender and each state has their own laws regarding it. Here in Utah it's 18 for boys and 16 for girls.

I'm in favor of age of consent reform. There are plenty of 13 and 14 year olds out there that have the mental acuity to consent to sex. I know I was at that age. I'd like to see some sort of standardized test or something that reasonably determines whether they're capable of giving informed consent. Of course, this would be something done only with the approval of the minor's legal guardian(s) since they're still legally responsible for what their kids do.