Need help recovering several lost savings bonds? Is there A way to get them back?

Hi Everybody. When I was young, for my Christening I recieved several bonds. My parents recently informed me of their existance and that they were lost somewhere when I was growing up but noone knows where they are. I am now 20 years old and they would have greatly increased in value. I was wondering if there is anyway for me to get them back or get the value in money of them back. How can I track/locate them. I do not have the serial nuimber of the bonds, don't specifically know the people who gave them to me, and no other pertinent info. I hear that back then when someone recieved a bond, the person who gave you the bond has their ss num,ber on the bond, not yours. Any help please I'm desperate?