If you plan to go into private practice and get paid out of pocket, do you have to get board certification?
You do not as written above.
However, if you expect to get paid out of pocket, most patients want to see some proof of your quality. Although I do not believe board-certification is a reliable index of good quality, it is one of the only ones available. Several will not want to shelf out a lot of money (out-of-pocket) if they do not see a board certification or a D.O. That is written with full acknowledgment that I don't believe that not being board-certified or being a D.O. means the person is a worse doctor.
(Some of the worst doctors I've seen are board-certified).
If you do run a private practice, several insurance companies will not accept you on their list of doctors they will reimburse without board certification. Some will, but on the declaration that you will get board certified in a specific time range or they'll eventually drop you.
As for seeing children, I agree with all of the above. I was recommended by a friend who was a forensic and child psychiatrist that it's not out of the question to see children, but if you are not a child psychiatrist, try to limit yourself to older children (e.g. age 16 or older), and on simple cases. Do not touch with a ten foot pole very complex cases (e.g. a 10 year old with schizophrenia), unless you're the only psychiatrist in the geographical area that can see the patient. Then, if you are in that situation where you're the only one, if you still choose to the see the patient, make full declaration of your limitations and suggest that the patient see someone who is better qualified.
Being the only one in the area can afford some legal protection. Remember, the standard of care is geographically based. If you are in an area where you are the only person who is psychiatrically trained (as is the case in several midwest states), the person may have no choice but to see you, and because of the geographically based standard, you are afforded some protection because no one else can be used as the standard.
That said, ethically, we still need to be aware of our limitations and refer out as needed. Simply because we may be the only one in the area does not give us free reign to do poor work or not warn our patients of our limits. They have the right to know that you may not be the ideal choice, but you are the best they may be able to get given their ability to see a doctor. You may still be on legal thin-ice. What I mentioned may be protective, but the best protection is to not get into the situation in the first place.
You may also want to consult a child-psychiatrist if you are in the above situation. E.g. the patient sees a child psychiatrist, but after the person is stabilized, you can be utilized to take over the stabilization. This would require some interplay between you and the child psychiatrist, and some child psychiatrists may not be willing to do this.