Even though William was now living with the Gadgets he wasn't an official Gadget. He was just William, with no last name. This of course was due to him and Penny dating. The dating started one night a month after Dr. Claw's defeat. They wanted to give William time to settle in first.
William, dressed up in a suit without a tie, waited by the front door for Penny. The Gadgetinis were there too, as chaperones. This wasn't because Gadget didn't trust Penny or William, it was because of the risk of Penny getting captured again. They didn't know if other villains had discovered Penny helping Gadget in the past but they didn't want to take any chances. Penny soon came down, in an attractive sleeveless pink dress. She wasn't the high-heels type, but she was wearing dress shoes. She also had her hair loose with a flower clip on one side. William was lovestruck over her appearance.
"Wow, I think cupid got me with an extra large arrow." William sighed, smiling with love.
Penny smiled and kissed his cheek.
They went out and had a great time. They first had dinner, but instead of a movie they went to a science exhibit in a museum.
Gadget and Jeanette also dated. Jeanette loved Gadget because he was the only guy she knew who was a combination of responsible, selfless, and fun. Gadget loved Jeanette because she was the only girl who ever loved him, smart or not, despite the clumsiness he had in the past.
Gadget and Jeanette eventually married but they never had any children. They didn't need to, Penny was already like a daughter to them. Even so Penny continued to call Gadget uncle and later called Jeanette aunt.
Years later Penny and William were officially hired by WOMP. Since they had already proven themselves as teenagers they were automatically made Lieutenants. As they continued working for WOMP they earned more promotions, until they were among the highest ranking officers. They never got higher than Gadget though, Gadget eventually became the next general after General Sir retired.
Penny and William were next to marry, and after they did they moved out and got a place of their own. The Gadgetinis went with them, since they always viewed Penny as their mom and now viewed William as their dad. And eventually the Gadgetinis got a little sister named Grace, after Grace Hopper the computer scientist. Oh, of course Brain went with them, being closer to Penny than to Gadget. Bein an anthro-dog allowed him to live longer than most other dogs.
The Gadget family continued stopping criminals, and with MAD permanently finished the world became a more peaceful place.