Once in a while people ask me questions for which I think it's worth preparing a few notes to respond. I've realized there might be value in keeping those notes - for future reference, or for others trying to answer similar questions. I'm posting those notes here. Notice these are not formal, the notes often include phrases that would not make it past peer review, and sometimes reflect my own opinions and values. I try to parse out what is simply fact, peer-reviewed research, or just my opinion, but I encourage you to read these critically.