I am an active user on Cognitive Sciences, and in the midst of establishing a tag on parenting, stumbled upon the section of your FAQ advertising "sister sites" on the exchange.
We would like to offer our site as a resource for asking child psychology and developmental psychology questions that might be on your users' minds, but are too theoretical to be on-topic for Parenting. The only minor limitation is that we discourage "self-help" questions, as those would be best answered by a professional.
Our developmental-psychology tag is fairly active, with 24 questions, including:
Our parenting tag is just getting started, but includes:
and more!
We have an existing question on our Meta about getting involved, so you are certainly welcome to leave your comments or concerns on this question or that one.