A method of gaming comprises the steps of: acquiring first biometric data of a game player by observing the game player through a button of the gaming machine when touched by the game player, in which the button also serves in operation of the gaming of the gaming machine. The first biometric data is compared with second biometric data provided by another source, for example, a "smart card" carried by the game player. Then, the gaming machine is activated for play by the game player if the first and second biometric data have a close similarity.