Unfortunately this is not always true. I am doing my thesis on false memories and false confessions. It is actually pretty easy to get a child to say what you want them to say. Also unfortunately, not all "trained psychologists" are looking out for the best interests of the child. If the psychologist is hired by/employed by LE, s/he may also believe the mother is guilty and feel like she is allowing the child to "open up".
If you can find the video of the Fox interrogation, you will see that the child said NO about 150 times. He was crying and begging for his parents. He was curled up in the fetal position, and they kept asking him. He finally said "maybe" and the let him go. This was just a few years ago. The Fox case is a great example, because Kevin Fox was absolutely, positively cleared after 8 months of horror.
Also, think back to the McMartin pre-school case, where trained psychologists GOT the children to tell how they were sexually abused by the staff. If you aren't familiar with that case - go look it up. It's scary.
Nope, I know too much about how it actually works. I would protect my other children, and protect myself as well. No interviews without a lawyer, full video-taping from start to finish, and probably even observation by a psychologist of my own choosing.