The Sacred Name Question

There are some who teach that our worship of God is not acceptable unless we address Him by use of his Hebrew name YHWH. Is this teaching Biblical? How would you answer someone if they approached you with this doctrine?

Gary Smith was born in Charlotte, North Carolina, but spent most of his youth in the Pasadena, California area. He graduated from Ambassador College in 1976 and he and his wife, Liz, moved to Peoria, Illinois. For the next six years he worked as a nursing home administrator in Illinois, Ohio, and Texas.
In 1982, he and Liz began to serve in the full-time ministry. Since that time, they have served in a number of congregations in the Midwest.
Gary and Liz now pastor in Houston, Texas near their two children and grandson.
Apart from pastoring, Gary enjoys hiking, playing and watching sports, reading and spending time with family.