Uber CEO Travis Kalanick is going to be 41-years-old in August. He's not some starry-eyed millennial with little real-world experience running a business. But if Uber ever wants to go public, Kalanick is going to need some adult supervision.

The ride-sharing giant has had one controversy after another during his watch. The latest scandal? A reported 2013 memo where Kalanick shares the dos and don'ts of a company trip, including whether or not employees can have sex with one another.

This comes just days after Uber terminated 20 workers following a sexual harassment probe.

Uber is also in the midst of a legal dispute with Waymo, the Google/Alphabet (GOOGL)-owned self-driving car company.

Waymo claims that former employee Anthony Levandowski took documents with him when he left Google to start autonomous trucking company Otto -- which was subsequently bought by Uber.

Levandowski was fired by Uber last month.

Kalanick has also come under fire for how he's interacted with workers. He was caught on video arguing with a driver about falling fares. Kalanick himself admitted earlier this year that he needs to "grow up."

"This is the first time I've been willing to admit that I need leadership help and I intend to get it," he added.

But how far does Kalanick need to go?

Related: Uber and its CEO try to grow up

Uber is the world's most valuable startup, currently worth nearly $70 billion. If it ever wants to be a publicly traded company, Kalanick will have to, at the very least, hire a deputy that Wall Street respects.

Some would argue Kalanick should just serve as chairman and that Uber should hire a CEO to handle the day-to-day operations.

That may not happen. But there is precedent for hot, founder-led tech companies to hire a Silicon Valley veteran that will give investors more confidence about how the company is run.

Facebook's (FB) Mark Zuckerberg tapped Sheryl Sandberg, formerly a top executive at Google, to be his COO in 2008. Facebook went public in 2012.

The Zuckerberg-Sandberg partnership is still working well, even as few people doubt Zuckerberg's Wall Street acumen and question his maturity anymore.

And Google (now Alphabet) tapped Eric Schmidt, a veteran of '90s tech giants Novell and Sun Microsystems, to be CEO in 2001. That was three years before Google's IPO. Schmidt replaced Google cofounder Larry Page, who was only 28 at the time.

Note a pattern here though? Both of these tech giants, which are now among the most valuable companies in the world, hired top executives years before they went public.

Uber may have to act sooner rather than later if it ever hopes to graduate from private unicorn to Wall Street darling. The clock is ticking.

Related: Uber fires 20 employees after sexual harassment probe

It doesn't help that the company is in the midst of a brain drain as well. In addition to Levandowski, president Jeff Jones stepped down in March. Product development head Ed Baker and mapping chief Brian McLendon have also left the company this year.

So Kalanick needs to find his Sheryl Sandberg or Eric Schmidt -- and sooner rather than later.