In my last two columns, I discussed the cases of young people who were placed on sex-offender registries because their sexual partners were below the age of consent. For the rest of their lives, any neighbor or employer who looks them up on the Web will be led to believe they are pedophiles.

This raises many questions, among them: What is the right age of consent?

The legal age is different everywhere. In Yemen, it's 9, although you have to be married. In Mexico, you can legally have sex as early as 12. In the United States, the age varies by state, ranging from 16 to 18.

For "20/20" I spoke to an 18-year-old boy who had sexual relations with a girl four years younger. Isn't that taking advantage of a 14-year-old? I asked.

"I wouldn't think so. I thought I was really gonna have a relationship."

What if she were 13?

"I really can't answer that question ... because she wasn't."

What if she were 12?

"Oh, heck no. There's a point where you draw the line somewhere."

But where? The law is at odds with what goes on in real life. The Centers for Disease Control reports that a quarter of America's teens say they had sex before they were 16. Since no state's age of consent is lower, millions of Americans must be breaking the law.

Some groups, like the Family Research Council, say the laws should be stricter.

"We oppose efforts to lower [the age of consent]," Peter Sprigg, its vice president for policy, told me.

But 17-year-olds are still going to have sex.

"Well, they are. But I think it's a legitimate goal of public policy to discourage that."

Making it illegal discourages it?

"There will be some deterrent effect presumably. That's what all of our laws do." Continued...