Well Vegeta has a second son called Tarble, so i wouldn't be surprised if Goku has a second son if Ithey make a new DBZ series or Movie.
I really hope your just new to dbz and didnt know what you said was all wrong. Now if you would like, i put in these spoiler tags on why the things you said are wrong..
that is soooo wrong. Tarble is his brother. Vegeta doesnt have a second son and but has a daughter which is Bulla who appeared at the end DBZ as a little girl. The only kids vegeta has had are Trunks and Bulla. And Goku already has a second son which is goten. He only has 2 kids like vegeta.
Bulla around the end of DB[IMG]https://encrypted-tbn3.************/images?q=tbn:ANd9GcSztvqI48BYpOJkK96jm3icsJNCQ3y5B v1CVML4KvCp_NtyX6cd[/IMG]