Step-Parents are LEGAL STRANGERS. Period.
While I respect your stance, amber_lynn ... let's take into account Step-Mothers that are overbearing, controlling and refuse to effectively coparent with the biological Mother and instead try to take over.
My son's Step-Mother LOVES signing her name that has anything to do w/ him. Medical records, school documents, etc. And it is rare that I am even notified of these documents that require permission.
Why should another woman be in control of and take charge over my child's important records? I feel it's not her place. So as much as no one should "sweat the small stuff", being kept informed of my child's documents and records is nothing "small". To me, it is vital and very important that the actual Mother and Father deal w/ these issues directly and for the Step-Parent to have enough respect to bow out gracefully.

Biological mothers need to chalk the ego. There is no logical reason that a step-mother that does not abuse the children or do things that hinder their growth and development should have to pay to support your kids and not have any other rights. Get over your jealousy issues and enjoy your children. If you're a good mommy... you have nothing to worry about. Honestly, if you can't work together with the step-mother you will just cause your kids more emotional harm. If you are the type of parent who cries and whines cause someone other than you is doing something for them... you should not have custody anyway.