cortisone? cortizal? health study targeting kids?

ok, so years ago when i was having my three babies all in a row... i was contacted to do some research... at the time, behavioral...

that was YEARS ago...

now they have contacted me for more behavioral study regarding my son... they presented it as, it is not part of the other study, but they want to check on the kids in the previous study... you get fifty bucks for the interview, the kids gets fifty bucks for the interview, then there is a twenty five dollar gift if i let them take a saliva sample to look for cortizal / cortisal (SP?) levels...

i told the lady no freakin way...

what are they really doing????????????