William Henry Gates III (father) Mary Maxwell Gates (mother)
William Henry Gates II (paternal grandfather) Lillian Elizabeth Rice (paternal grandmother) James Willard Maxwell (maternal grandfather) Adele Thompson (maternal grandmother) William Henry Gates I (great grandfather)
Jennifer Gates Rory Gates Phoebe Gates
Kristianne Gates Libby Gates
Elaine Agnes Amerland (mother-in-law) Raymond Joseph French Jr. (father-in-law)
William Henry "Billy" Gates IV is a former godson of Cosmo and Wanda. He is based on the famous real-life creator computer mogul and creator of Microsoft, Bill Gates.
Billy Gates is a nerdy looking boy who was the former godchild of Cosmo and Wanda in the 1970. A time travelling Timmy Turner ran into Billy Gates.
When he appears as a child in 1970s Dimmsdale, he has a brown afro, thick coke bottle glasses, and a teal blue shirt. He speaks with a nasally voice like Elmer, which is not odd, because Billy shares the same voice actor as Elmer.
Billy Gates has appeared twice in the show. In "Father Time!", his first appearance, he is shown returning from traveling in time with younger Cosmo and Wanda from the 1940s just in time when Timmy was arriving in 1970. In this episode, after Cosmo and Wanda showing a computer of downloading lava lamps, he devised the idea of creating Internet. Cosmo suggests he name it "The Timmy" instead, and Billy takes his advice. When Timmy returned to the future, he found that Billy Gates ended up taking present Cosmo's advice and that the Internet was named after him (and Timmy was named "Internet").
In "Hassle in the Castle", he is shown in a portrait in the Hall of Fame in Cosmo and Wanda's castle, indicating that he was a good godchild.