yea these have been around for quite a while...ive haerd of them, the concept behind them makes sense if you ask me. take a group of children and expose them to a child who has chicken pox to infect the children without, that way it is easily controllable and containable from the start, therfore eliminating the chance of getting it later on at an inopportune time. i agree with the idea. especially since i spent my 11th birthday with chicken pox and couldnt do shit!