There's no doubt that one of the most controversial and discussed topics in MMA right now is Performance Enhancing Drug (PED) use. Former Lightweight champion BJ Penn has always been extremely outspoken against their use for anyone in the sport and that isn't stopping now. A couple weeks ago Penn agreed to fulfill his UFC contract with a match against up and comer Rory MacDonald. Today he announced on twitter that he'll be accepting VADA's offer to sponsor their bout and asks Rory to do the same:

From Penn's Twitter Acccount:

. @rory_macdonald VADA anti-doping has offered to sponsor our upcoming fight.I've accepted and invite you to help me clean up the sport

No word yet on whether Rory Macdonald will accept Penn's invitation. But it will be interesting to watch this play out. To the best of my knowledge this will be the first time in both UFC and MMA history where either one or both fighters in a match agree to any testing further than that required by the local SAC.

UPDATE: Rory wasted no time in responding to B.J Penn's challenge, with a nice little jab of his own to boot:

@bjpenndotcom already worried BJ? honestly i think its a great idea 2, and im ready to do the testing for our fight aswell @danawhite