Dr. McMullen conducted research at three government laboratories and taught at four universities. He has two degrees in engineering and two in the History and Philosophy of Science. He was baptized at an early age, but in college, he went his own way. God called him back to Himself through Jesus Christ in 1969, and he has endeavored to live more biblically since then. He and his wife met at the Air Force Rocket Propulsion Laboratory and have been married for 57 years. They have two children, five grandchildren, and four great-grandchildren.