I was watching this episode on criminal minds where these people do something for a ritual is it true?

Sure, it can happen. Of course the shows version is fiction. Kidnappings happen all the time, all you have to do is look at this past year for two examples of someone being held against their will and bearing their abductors children (Josef Fritzl & Phillip Garrido). Sometimes that person can be held against their will their entire life or in the case Stockholm syndrome, they get attached to their abductor and freely stay with them. Once they have kids, and aren't caught, they can influence their children anyway they want.