I'd tell him BM asked you to talk to SD because she's getting "that age".  I wouldn't mention the kiss which is hearsay anyway.  Your SD is probably showing signs of maturity and might have already begun menstruation.  I'd tell him you are flattered but are concerned since these talks usually come from a parent.  He will probably be glad to have you do this since he isn't very involved.  But I'd use this occasion to discuss the whole topic of his and BM's relationship with SD.  I think your Instincts are correct to proceed with caution.

That is definitely weird that BM asked you to talk to her.  As the mother of a daughter myself, I would never leave this up to someone else. The only exception would be if I was dead, then it would fall on my husband to either talk to her or have a close female family member talk to her.  I would think that BM would want to handle this herself, since she is her mother.  I second bringing your husband into this, though he'll probably tell you to just give her the talk already.  

Of course, you should tell your DH that BM asked you to talk with SD about this.  No.. of course you don't have to share the kiss thing with him.. it's hearsay... and honestly, it's not life or death really right? (except covid..haha).

I imagine she knows more than her mom thinks at 13 years old.  Certainly her peers know more.. have older siblings.. have had parents that have had the talk.  Also, I'm fairly certain by that age some stuff like periods have been covered at school.

I guess the big thing you would need to know from  her parents is what do they want relayed?  Their boundaries about what they find acceptable for when she can start dating.. what level of intimacy they will find morally acceptable? Do they want you to talk about BC with her?  Would they want her ON it? Safety issues? Sanitary issues? Moral issues? 

I mean, my mom didn't give me the best talk... it was pretty much "sex can feel good but have consequences".. not really a deterrent in my underdeveloped mind.  haha.

I didn't ever have "the talk" really.. but over the years I did have talks (at my YSD's questioning) about some things from time to time.  I tried to not make decisions for her parents.. but tried to be open and receptive to her questions and answer them as factually as possible.

SD is 13. Eighth grade? Now I realize that things are different in different places, but if SD is in school, she may have had classes that touched on this.  Schools here do a form of the talk in fifth grade. So I don't think you will be starting from scratch.

SD hasn't told any of her parents about the kiss. I'm not surprised. Most kids don't. She's growing up. Teens don't usually tell their parents much.

Take your clues from SD. She may want to talk. She may not want to talk. If she doesn't want to talk let her know you are open to a conversation if she decides she wants to talk.

Nope, I wouldn't do it. It seems like BOTH of these parents want you to pick up their slack, and that isn't good for you or SD.

I'd tell my DH about BM's request, but probably spin it as "Can you believe BM would try to get me to do something that you and she need to handle together? Sheesh, I'm not the parent, you guys are."

I would leave them alone and give them the time needed to be together. It's nice you get along with her but a girl needs her dad.  Maybe he can take her shopping for gifts. So what if it awkward and painful.  They will need to learn to get past that stage.   Maybe a project around the house,  a chore they do together (like cleaning up dinner and dishes).  It's those boring times doing things together where relationships are formed between parent and tween.  I'd step back a bit and "force" them together with easy ways for them to be together.  I did this for my girls and they are much better off than my skids for whom BM cut them up off from DH.    IMO.  As for talk, give her the basics, please don't send another ignorant girl out into the world. Her dad would be a good one to explain the puberty mindset of a boy and set her straight on what to expect out of a boyfriend.  

I'm of two minds on this. On the one hand, this is 100% BM and DH's responsibility. On the other, if they aren't going to do it, I personally wouldn't want to leave SD to her own devices to find answers. In the US, we do a piss-poor job preparing kids and young adults for relationships, intimacy, and eventually sex. We don't teach consent consistently, other than the occasional 30-minute program on "bad touch". While kids may understand the biology and pathology of sex (if they're lucky), anything beyond that is spotty. It's how young adults end up in toxic relationships, and not exploring their own pleasure and relying on others to try and bring that to them.

I say all this to say that it's NOT your job to cover this topic, but I think you can be a conduit for information. I think you can point out toxic relationships or dangerous situations in the horror movies you watch. I think you can listen when she has questions and funnel concerns to her parents. I think you can correct any misinformation she shares. I also think you can encourage her to talk to her parents about this.

Basically, you can passively guide her while being firm with her parents that they need to address this directly with her. That way you aren't directly on the front lines educating her, but she's also not rudderless as she navigates this. 

I have had a few versions of "the talk" with OSS, and will likely do the same with YSS. But, I'm specifically addressing some LGBTQ+ questions and concerns that DH is less equipped to answer (part of my professional field is sexual health education). Morality, house rules around having partners over or dating, personal relationship issues - those go to DH. If I see something concerning, I'll speak up, but mostly I leave those things to DH to help guide his kids. That is not an approach you have to take; you can be completely hands-off. But there is totally a way to let SD know you care and can be a person she comes to without being the one coordinating SD's sex ed.

Particularly regarding anything to do with his child.  Yes, she is your SD, you are  he closest parental influence.

But... secrets are not a good idea. 

I have kept one secret from my wife in our 27+ year marriage and it was about my SS.  

I caught him surfing gay porn when he was 17.  I sat down and we talked. i asked him if he had anything to tell his mom and I and let him know that we were there for him no matter what.  He swore up and down that he had clicked thre wrong field on the porn site.  I did not go into pulling teeth mode to get to the full facts. I just let him know that if he was gay that he was our son and we loved him.  Then he asked me not to tell his mom that he was surfing porn. I respected that request.

Meanwhile 5 years later and when his mom and I were living in Qatar, he called us on Christmas day for our usual call when we are not all together.   After the usual Christmas wishes, I love you's, etc.. .he started getting weird and obviously had something he wanted to talk about.  I finally told him to just get it out and not to worry about his mom and I and to rest assured that we had his back.  At that time he came out to his mom and I that he is gay.  His mom was all shocked and surprised.  I was not as I had suspected since he was in his early teens and... we had gone through the gay porn incident together.

When DW expressed her surprise and comforted him with the clear massage that he was loved and it did not matter in the least other than she was happy that he could not be happy SS said "You had to know mom. Mom's always know. Besides, dad knew and you guys tell each other everything."

Nope kid, I honored your request not to tell your mom.  So, I was on the Bride's shit list for Christmas that year.

Tell dad. if he wants to engage, great.  But, do not risk him finding out by surprise.. 

If you feel comfortable doing it, go ahead and do it. For the most part, I stayed out of parenting my SD when she was in her teens. However, I made it my mission to make sure she got through high school without getting pregnant. With the blessing of my DH, I took her to Planned Parenthood when she was 16 and her Mom wouldn't take her. Fortunately, the blow back was minimal because SD didn't tell BM about it until she was 18. Helping a girl avoid pregnancy is one area where I think pushing boundaries is ok.

Your SD is 13 and has already kissed a boy. She already knows way more than either of her parents realize. What she needs now is practical knowledge that will help her keep from getting pregnant and keep her from going farther then she is ready to go.

I wouldn't do it - BM can talk to her own daughter about it. I would tell DH about it though, I personally would not have a secret with my DH's ex or kid hanging over my head, and he'd be mad if I did. Yours is more hands off than mine was though. 
 

Sad that both parents would rather have you be the parent than ever be "the bad guy". Be prepared for your SD to realize you are the only one with rules and begin to resent you. 

---I guess what I'm asking for here is, how would everyone else approach this?  Do I tell her dad (not about the kiss but about needing "the talk"), do I just talk to her, do I bounce it back on BM?  I should also mention I'm in public health so I'm well qualified, just kind of not sure how to give her the talk and not have her dad involved at all.---

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Hmmmm

I think YOU believe that YOU are doing the right thing. One tiny problem, sd is not your child. First, You should NOT keep secrets from your husband. Then go behind his back to give his daughter the talk. It doesn't matter if you work in Public Health, or are ob/gyn OR PP worker, THIS is not your place. 

I get it, you have a great relationship with sd. That is all well and good. Separate from the fact that sd is not your child. 

Lets go further, maybe, BM is a total flake. DH still thinks his daughter is 6 when in fact she is 13.  Even IF true, you still should step back. Let bm and dh handle it.  Perhaps bring your concerns up in a therapeutic setting.  My hunch is there is more to this. 

What's next? IF sd came to you and asked YOU for access to Birth Control pills OR IUD...would you take her without her parents knowing? Or if she becomes pregnant, will you talk her to PP.  Are you going to keep all this a secret too? 

You seem pretty hard pressed to step IN, willing to make unilateral decisions about someone else's child. Why is that?

It is best you let BIO MOM and BIO DAD deal with everything pertaining to their own child.  When a issue arises simply say,   darling---did you KNOW daughter DID or IS blah blah blah.

Anyway best of luck to you. 

NOPE, not your responsibility. 

I talked to SD about menstration, but ONLY because it was an emergency. She was home alone with me when she got her first period and had no clue what was going on. I gave her a pad, but was SUPER vague about what and why periods happened. I texted DH about it, then he in turn told BM and she had "the talk." 

Honestly, I would stay out of it. What happens when your SD gets older and has questions about birth control, etc.? Do you want THAT responsibility to fall on you too??