My wife and I early on banned the term "you're not my father" from our household.

http://blogs.trb.com/features/family/parenting/blog/2008/02/looks_like_i_missed_a_step.html

I consider myself lucky in that the girls were old enough to understand that I wasn't there to replace their dad, but to support their mom. There are time when they defy me (usually in the form of challenging my right to take part in a conversation).

But those are teens. If Miami Mom is dealing with a 3-year-old, then I say handle it like she's your daughter. If she reminds you that you're not her mommy, then you can tell her that her mommy wouldn't put up with misbehavior and neither will you.

Not professional advice, I know, but it's what comes to mind.

Good luck with it. We stepparents have to stick together! I've written a bit on stepparenting, but not from the perspective of raising a toddler.

http://blogs.trb.com/features/family/parenting/blog/stepparenting/

Open communication between step parents and parents is the best place to start. Discuss who should handle the disciplining and how it should be handled. Clarify the roles and boundaries of respect for the step parents with the understanding that the parents will support decisions on consequences previously aggreed upon by the "caucus". I've found that consistency or carry-over consequences, work well. Where a consequence carries over to the other home should it be deemed. Step children will "play" the step parents and parents against each other if there is a kink in the armor. Have a plan in place to keep the consistency and make sure you all know what is going on - a lapse in communication is a kink.

Tutor : Great advice! I know the parent has found this helpful.

I have been stepparent TWICE. My oldest step son is now 22 and always calls me and we have a better reationship than he does with his dad. Kids will play out any situation. My step son now is just 4 years old. First and foremost you need to explain to the kid that your are not replacing their real parent, but that you are an addition to her/his extended family. Then make sure that you explain that while they are with you they will be treated just like the other kids in the family.(in my case, I have two other kids)Then make sure that ALL PARENTS are on the same LOOP. I explained to my step son Bryan long ago that in our house we are all the same and share the same priviledges and we all have chores and responsibilities. We all do things together as a family and while he's with me I am responsible for him and he must respect me at all cost. If a 3, 4, or 5 year old is mean and rude, or disrespectful to adults it's up to the BIOLOGICAL parent to address the issue. If this happens in my house I will take matters in my own hands and dicipline the kid according to his age & cause. In my houe we are EITHER ALL WHITE OR ALL BALCK, this goes for friend of my kids also.... We just do not tolerate
DISRESPECT at all, and that's that. Teaching kids what to expect is a great benefit. I learned all this from whom. The best STEP MOTHER one can have.
My step mother CECILIA.
Boy, she proved to me that the CINDERELLA STEP MOM is one in a MILLION.... Most step parents care and you cannot fool a kid when it comes to that. Give them LOVE, ATTENTION, DISCIPLINE,
MORE LOVE, Understanding, hugs and kisses, play with the kids. Believe me you can win them OVEr in less time than you think....
A Step parent of two and parent of three....
Gotta Love those KIDS.....

Evelyn : Thanks for the sage advice. What a great example of parenting.

I want to thank you all for the great advice i have received, all this makes sense to me. It is what it is, i am a step mother and I love her like if she was my own, but when it comes to discipline I do have my boundaires, but I am thankful to have a partner that supports my decisions and helps me with the situation. He helps me by telling her to listen to me when I am talking to her or when I am telling her soomething and she doesnt pay attention he is the one that steps in and tells her "anita is talking to you, dont do this or listen to her" and that helps me a lot. It is not that my 3 year old is being disrespectful is that so far she hasnt learned to comeplty listen to me and that is what we are working on. I need to give my respect as a step parent, because even if im not the real mother, in the end, when she is with me I am the resposible one for her. it is up to me to teach her the right things, as long as she is in my care. Thank you all for the help!

I agree that both parents and step-parents should openly discuss how to dsicipline children. Both households should be respected by everyone in which sometimes may be difficult if there is difficult communication with parents. Time outs worked best for me and when things got a little difficult, me being a stepmom, I involved the parent and they would handle.