That sounds like an upsetting theory, Dnester. Did she explain to you what made this idea pop into her head? Something like "Sometimes when clients are experiencing X it can be related to childhood abuse" or similar?

I think theories can be helpful if they are given in a spirit of open-minded curiosity and exploration, and the thought behind them is explained, and the T is not wedded to any of their theories. But this theory is a bit of a bombshell, and feels like something a T should suggest only very carefully and with a lot to base it on.