Should I tell my child my partner is not their biological parent?

I think it depends on the childs age, and mental state. I was only recently told that there's a high chance that my father isn't my biological parent, but being in my 20's, I don't mind. He is my dad as far as I'm concerned, because I believe being a parent stems from actions, not entirely from blood. I'm glad I wasn't told when I was younger, I don't think I would of handled it well.

Most certainly, in most cases it is shown that a child finding out on their own could be detrimental in more ways than one. While studying sociology & psychology all information pointed me towards telling a child early on, but reinforcing the love of the non-biological parent. A constant relationship is necessary with the NBP before you consider doing this, or it could cause a domino effect of harm.

Has the child asked the question? This one seems to fall under the "if it is not broken, do not fix it" category. To give a reasonable answer, more information is needed; at least more information would be needed by me.

Yes. Yes, yes and more yes. If they're of an appropriate age to understand, then they should know. Likelihood is, they're going to find out eventually, and if you've hidden it from them, that pent up anger is going to be directed at you.

Reverse the situation for your answer. Let's say one day you stumbled upon the fact that one of YOUR parents was not biological. Do you think the revelation would be easier for you to handle had they told you about it previously?

Although as a circumstance of their environment children will always question their mold. Any hints help

Your child would want to know the truth. But don't just flat out tell them. Explain everything, and make sure they still know that you love them. This can be very struggling, but the longer you keep it from them, the more it will bother you and the angrier they will become. It's better to be honest with everyone.

I think that depends on the circumstances. But I am a big believer in honesty being the best policy. The child will be curious about where they come from and that is natural. It is up to the parents about what choice they want to make and what will be best for their family.

If I were the parent of a rebellious teen I don't think I would tell the person about being adopted.

Yes and the earlier the better. It's always better to be honest and upfront with your kids, it is possible that they will react in a negative way when you tell them but in the long run they will appreciate that you spoke the truth.

Yes. I have a friend who once told her child that her father wasn’t her real dad. You don’t have to do the following, but I’d advise what she did. You could try saying, “Hi, can we have a talk? Don’t worry, you didn’t do anything wrong. It’s just about your family past.” Then sit down, and say, “You see, your dad/mom isn’t your biological dad/mom. There was somebody else.” Answer questions, explain gently, give lots of hugs, and give a lot of support. Another idea is to wait for a few years until it seems you’d both be ready for it. Or, if you want to do it now, you could say, “Try not to judge your dad/mom, but he’s/she’s not your first one. You see, can we talk about it? You had another dad/mom before the new one came along. Don’t worry.” Or you could innocently say, “That’s just like what your first dad/mom did/said/thought/saw/heard. Oh, you see, your dad/mom isn’t your biological one.” This blasts off a family talk, kisses, hugs, and love required.

Yes . The child should know the truth. Whatever may happen but it's never good or fair enough to build a good relationship on a lie.

I believe that honesty is the best policy. But you have to do what you are most comfortable with in the long run. Sometimes being calm with someone and scheduling a time to have a serious conversation helps and saying it in a nice way to keep the conversation light is a nice way as well. You have to go into the conversation understanding all of the risks but also understanding all of the benefits. You just need to be prepared and I've noticed saying one or two good things first helps bring out the bad news. Ice cream never hurts either!