Is it against the law to talk on a cell phone and drive in the state of Missouri?

I just spoke to a police officer and he said that it is not illegal to text or talk on a cell phone while driving YET. They are trying to pass it as a law. A law was recently past that it is illegal to drive and text under the age of 21yrs. in the state of MO. Now you can and probably will be found guilty if you are on the phone talking and are involved in an accident.