Emily Yoffe, aka Dear Prudence, is on Washingtonpost.com weekly to chat live with readers. An edited transcript of this week’s chat is below. ( Sign up here  to get Dear Prudence delivered to your inbox each week. Read Prudie’s Slate columns  here . Send questions to Prudence at prudence@slate.com .)

Emily Yoffe: Good afternoon. Let's get to it.

Q. Pregnant High School Friend: My best friend, "Kris," and I are sophomores in high school. We've been best friends since grade school, and so I'm really in shock about what's happening to my friend and how she's dealing with it. Kris and I are in the same history class. There's this really awkward boy in our class named "Herman." Sometimes when the teacher goes out of the room, Herman covers his lap with his coat, puts his hands under the coat, and wiggles around a bit. No one ever says anything, but they make fun of him a lot out of class. Last week, Kris confessed to me that she's pregnant. She says that when we were doing group work in class, she sat in Herman's chair, and the chair was wet, but I don't believe her. That's not even possible, is it? I think she's making this up because her parents are very religious and are going to flip out. Now I'm really confused. Should I just tell Kris I don't believe her, and that what she's saying is wrong, or should I go to the principal or counselor or someone? Kris says her parents don't know yet.

A: Kris needs to let go of the fantasies of Herman the sperminator and make some serious decisions, and soon, about this pregnancy. She needs to see a doctor, tell her parents, and identify the father. As a friend, you should encourage her to get the medical and emotional help she needs as soon as possible. If she won't act, then tell her you are going to tell your own parents and the school counselor because every pregnant woman needs medical care. I suppose if this ends up being an immaculate conception, that fact should mollify her very religious parents. I also hope Kris is not spreading the story about Herman around school about Herman spreading his seed. It sounds as if he needs help, too, but no one should be the victim of false accusations.

Dear Prudence: Lecherous Neighborhood Father

Q. Engagement Photo Catastrophe: My son is getting married in a few months to a smart, funny, and pretty young woman. They recently had their engagement photos taken by a professional photographer, and the photo shoot included taking a handful of "silly pics" along with the more traditional ones. The problem is that my son's future mother-in-law shared a couple of the silly pics with her friends on Facebook, and in turn one of her friends, as a joke, had one of the silly pics published in the local newspaper in the engagement announcements. My son is pretty upset with his mother-in-law-to-be, but not as much as I am. He says he's willing to just let it go for the sake of not getting off to a rocky start, but I'm not willing to just sit and watch while he gets pushed around. I want to teach her a lesson. How can I help my son understand that it's not a good idea to just let his in-laws step all over him?

A: Last week I had a letter about a mother-in-law who was possibly poisoning her daughter-in-law. Many people wrote in to say a few drops of Visine in food can cause unpleasant eruptions. So maybe you can give your son a bottle of Visine to season his future mother-in-law's next meal. That will fix her! What you're so angry about is some silliness that got out of hand. The bride's mother didn't send the photo to the newspaper, a so-called friend of hers did. You may not want your son to be "pushed around" by his future in-laws, but if you don't put a lid on your own behavior, you're going to be one of those crazy mothers-in-law I get letters about.

Update, March 13, 2012: To eliminate  any confusion, I am against poisoning people, even the annoying. Ingesting Visine can be lethal .

Q. Stranger Mom: When I was 6 my mom left, and we haven't seen her since dad remarried. Now, 26 years later, my maternal uncle contacted me with the news that my mom was disabled (no other detail) and she really wanted to see me. She apparently contacted my brother a year ago, but he didn't respond. He said she doesn't need any financial help, but she simply wanted to get in touch with us. Oddly, he also mentioned that she lives with her sister, who is getting on in years. To me it sounded like he was suggesting there was nobody to look after her and she eventually wanted me to care for her. My aunt on Dad's side thinks I should meet her at least once. I don't think I'd even recognize her on the street. I don't really want anything to do with her, but am I being cold hearted?

A: If you were someone who'd wondered all these years who your mother is and why she left, then you would be feeling differently about this contact. But for you the mystery is why now, after all these years, she suddenly wants to get in touch. For you, and apparently your brother as well, this is a mystery best left unsolved. You are not cold-hearted to want to keep your life as it is without unearthing what must have been very traumatic memories. Your aunt expressed her opinion about what you should do, but you disagree. Declining contact is a perfectly reasonable response and one you don't have to explain or defend.

Q. Dad's Girlfriend Hates Me: My dad's girlfriend proclaims she hates/is allergic to kids on Facebook. When my brother and I spend the night at their house (every weekend), she stays in the bedroom until we go to bed. She complains that my little brother, 10, only plays video games. But she rejects his frequent requests to read or do a puzzle. She also turns down my invites to go for a walk or to a museum. My dad says he respects her right to not want kids. I'm 16 and very protective of my brother. I don't feel we're welcome in our dad's home anymore. We love him, but I'm so scared he's chosen her over us. Mom doesn't know, because she'd flip. She married a man who loves us. I don't know what to do and feel so lost.