Teens for Christ was the predecessor of the Children of God. It was first used in 1966 as the name of a singing group and travelling Christian ministry run by David Berg and members of his family.
EVE & KIDS ALSO RAN THE CHURCH IN THE HOME EXHIBIT AT THE NEW YORK WORLD'S FAIR until we struck
out on the evangelistic road again by faith with family of six plus Josh, Caleb, Lydia & others in our 26-foot camper as "Teens for Christ" in 1966 with mimeod "Warning Tract" as our only lit!
Source: 1942! --A YEAR OF DELIVERANCE! (DO 1723)
In December 1967, at the invitation of Berg's mother, the "Teens for Christ" went to California to help out with a Christian coffeehouse and outreach mission run by Teen Challenge and David Wilkerson.
78.MOTHER INVITED US THEN TO COME TO CALIFORNIA TO WORK WITH THE HIPPIES, so with our little Teens for Christ team we hit the road again & went to California in the Camper & spent Christmas 1967 with my Mother. Then we worked there at Huntington Beach all next year, '68 & you came in January '69, & we left there in April driven out by persecution.
Source: HAPPY DAZE!--By Father David (DO 958, 6 December 1980)
In the book Children of God: The Inside Story, Berg's daughter Deborah Davis recalled how the "Teens for Christ" eventually took over the Teen Challenge mission:
At first, the Berg team simply helped out witnessing and assisting the Teen Challenge staff. However, they proved so effective, that they were given access to the mission for their use, on weekdays, when it was normally closed. Singing together as a group, they called themselves "Teens for Christ." They had great appeal to the youth. Soon, the Berg family began to pack the place on weeknights. Teens for Christ had discovered the secret to gathering lost and wayward youth: Free peanut butter sandwiches and live music. It wasn't long before Teen Challenge realized that the Berg family had the key; feed the stomach and the spirit; and gladly turned the mission over to the industrious Teens for Christ.
Source: Deborah Davis, "The Children of God: The Inside Story." Chapter 3, "The Gospel of Rebellion." 1984.