Yes you should since teenagers don't always show the best judgment. You should talk to her about it just to be sure though.

Date; An appointment or an engagement to go out socially with another person... You should be concerned about your friends actions with the 25 year old before there are negative consequences.

Edit: Answer below invalid, disregard. Hell yes. You are going to become a grandparent way too soon if you don't intervene, thus giving your entire family a "redneck aura" and your relatives with ostracise you and your daughter. Not only that, one thing will lead to another and you'll have a statutory rape on your hands. She won't like it but you must sever their bond NOW.

Yes, you should try to find out what they are up to, if it is just more than a friendship. Then you tell her parents asking them to let your name remain anonymous because she is way too young for him and most of the time older man seek young girls to use them.

You should definitely step in. You may think you know him well enough to know he wont touch her, but you may not actually know him. When I was 16, I was seeing a 21 year old man. My friend claimed that she knew him well and that he wouldnt harm me or try anything, and he did when he got me alone. This could get way out of hand.

yes, it is abnormal for a 25 yr old to "befriend" a 16 yr old

yes be worried. no offense to your friend. but a 16 year old really doesn't have much to offer to a 25 year old, unless its sex. that is the more than likely reason the older man is trying to "befriend".

you should talk to her parents. its illegal. she is probably giving him blow jobs. . now two and a half years later, she is over eightteen, they are probably married with two kids.

You should be very concerned. It is illegal & just not right for a man of 25 to be going out & spending time with a 16 yr. old girl.

It seems unwholesome, but I seriously doubt there's a problem. It's more a matter of what the guy's problem is. Is there a power imbalance? Probably not, as long as it's consensual. Is she going to be traumatized? I doubt it. The worst part will be when it (inevitably) collapses and she becomes an emotional wreck, but that could happen with a guy her age.

YES, make sure that your friend knows that no matter who says what if they get physically serious he will go to jail.

Should you be concerned? Yes. However, she's not exactly consorting with the the Prince of Darkness, nor is anything you've described in and of itself illegal. I'm quite sure that it's perfectly acceptable for the two to spend time together, provided she has her parents consent (this I believe is where matters of statutory (sp) rape may come into play, depending on the laws where you live). Morally wrong, but unless you have proof however of some more physical interaction though, not illegal. At any rate, her parents should know about it, and let them handle it from there. If she has her parents consent, and you think they're having sex (or know they are, and or she lies to her parents about it to get consent about the relationship) I would think your options would be quite limited to making sure she's safe in her practices, as it were, and maybe to make sure she's thinking it through. My reason for not joining the outrage bandwagon is simply that many of us, I think, have parents whose age could be separated by 6-10 years, or more. If your parents were high school sweethearts, captain of the football team and homecoming queen or what have you, good for them, but I don't think it's necessarily the rule. I also find it hard to accept that, looking backwards in time and taking the age spread into consideration, that these kind of relationships haven't always been as commonplace as we now see them happening. Needless to say, be concerned, but don't necessarily think the situation is as sinister as some would imply.

Get her away from him right now! It is not in the least bit appropriate for him to be hanging out with her, much less dating or anything else. He is an adult, she is a child. You are her parent. Stop all activity that does not include family involvement.