dhcp mac spoofing

Hi
i want to stop mac address spoofing in dhcp , when mac address is spoofed with the same mac address in dhcp lease he get the same ip in dhcp lease that mac permission to get ip address, what i want to do is only one mac address get ip even when he spoof mac address.

i have dhcp in static mode

http://forum.mikrotik.com/t/no-ip-scanners-nomore-updated/110846/1