Thanks Sabresite for reply, but i think i found something, today i was searching for female ralts in Heartgold, i use a male jigglypuff with cute charm, and only one female ralts has a large PID, the others have short PIDs, also i catched male ralts and ditto, and they have normal PID, maybe this ability change the gender altering the PID.
EDIT: I catch more ralts without the jigglypuff in my party and all the pokemon i catched has large PIDs.
ralts.zip
ralts with large PIDs.zip