The German retired abruptly at the end of last season after beating Mercedes team mate Lewis Hamilton to the title and becoming the second son of a champion to win the championship.
Finnish father Keke was world champion in 1982.
"I just from my dad genetically inherited a natural gift to drive racing cars," Rosberg, who is now looking at technology startup companies, told an event in London organised by Wired magazine.
"I’m a firm believer that genetics are quite a big part of this...I would probably say 66 percent genetics, 33 percent nurtured," he added.
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"I would go to that extreme. In our sport it’s very clear..."
Referring to Red Bull's Max Verstappen, whom he dubbed "the crazy Dutchman", Rosberg cited the 20-year-old triple race winner as an example.
"His dad (Jos) was a successful driver too and now his son is a successful driver because it’s the genes that pass on," he added.
Hamilton, who became Britain's most successful driver and a four times world champion in Mexico last Sunday, goes against that narrative, however, as someone with no family background in motor racing.
Without giving examples, Rosberg said many Formula One drivers had personality traits that were both a strength and weakness.
"The general Formula One driver is a big narcissist, in love with himself and he thinks he’s the best in the world and it’s always the other guy’s fault," he said.
"That gives you a certain strength in this crazy environment where you are judged by millions of people every little moment but it’s also a weakness because you don’t question yourself as much.
"I was more on the other side, the more sensitive, less narcissistic. Questioning myself all the time, trying to improve step by step."
Rosberg said he had to show total dedication to win the title. He hired a mental trainer and learned to simplify life, practising meditation to bring greater clarity and focus to his racing.
(Reporting by Alan Baldwin, editing by Toby Davis)
