Nov. 7, 2013, marked the first Parents Day at LinkedIn offices in the Empire State Building, Manhattan, New York. Photo by ©Jennifer S. Altman 2013 All Rights Reserved

When David Henderson was 10 years old, he spent a day with his mother at the Lawrence Livermore National Laboratory in northern California, getting a close-up view of her work as an information technology specialist. Twenty years later, the tables have turned.

Last November, Henderson brought his mother to LinkedIn's Mountain View, Calif. offices so she could learn more about his job as a project manager there. As part of LinkedIn's first Bring In Your Parents Day, Henderson's mom got to meet his colleagues, tour the company's 25-acre campus and take her pick of the free the panini bar. Or Indian fare. Or local handcrafted Philz coffee.

"She works in more of a government workplace and we've got an executive chef that came from Mustards," Henderson says, referencing the landmark Napa Valley restaurant where LinkedIn's executive chef once worked. "It wasn't something she could have imagined."

On Nov. 6, LinkedIn will again roll out the welcome mat for its employees' parents, and has convinced more than 30 other companies to do so as well. Virgin Group, SAP, British Airways and advertising agency Leo Burnett are among those opening their doors on the same day, in a flip of sorts on the traditional corporate career visit for kids.

Other companies, such as Google and Northwestern Mutual, have launched similar programs on their own in recent years, inviting parents in for welcome days or for open houses while their children are interns.

"It's not like parents are popping in all the time for coffee, but I think it's slowly becoming more accepted," says Hannah Ubl, a consultant with BridgeWorks, a generational research and strategy firm. "There's this moment where companies are like, 'We're going to start working with you rather than against you,' and they've started doing this with parents."

For years, after all, companies have worried about the growing threat of an invasive species known as the helicopter parent. The hyper-involved moms and dads of the millennial generation were said to be showing up at job interviews, calling hiring managers on behalf of their kids and even complaining to employers about their children's salaries.

Older managers often saw this dynamic as dysfunctional and a workplace burden, says Neil Howe, author of Millennials in the Workplace. So much so, in fact, that when he began predicting a decade ago that companies would one day have events like this, "everyone thought it was funny. It was utter disbelief." A typical response? "Over my dead body."

Yet now that the oldest millennials have been in the workplace for a number of years, several companies are starting to embrace employees' parents as an asset rather than a hindrance. "The fact of the matter is it hasn't been a problem," says Rich Stoddart, CEO of Leo Burnett North America. "Look, if our employees' parents appreciate the culture of the company and the kinds of things their children do, those employees are going to be happier and more connected and more loyal to our company."

If there's any common theme to why companies have started involving parents more, that's it: Showing the workplace off to parents, and better communicating with them, could stoke higher engagement among employees and make them less likely to leave. "If their kids say they want to do something else," Stoddart says, parents "might just ask, are you sure you want to do that?"

Some companies playing host to families are careful not to link the idea to millennials. LinkedIn, for instance, casts its effort as both an employee program and a branding exercise. Meanwhile, a Google spokesperson says its Take Your Parents to Work event, which began in 2012, is simply a fun way to share more about the company with employees' parents, whatever their age.

PepsiCo CEO Indra Nooyi, for example, told Fortune earlier this year that she writes letters to the parents of senior leaders on her executive team, and she even called the parent of one high-potential candidate for help persuading him to join the company. When the candidate tried to tell his mother he was going to take another job, she told him Nooyi had called and said he should work at Pepsi. "I had no choice!" Nooyi recounted him saying. "Can you imagine going home every day after that and a mom goes, 'but you should have accepted that offer!'"

Northwestern Mutual has also discovered that cracking the door open to parents can have a payoff with potential recruits. Five years ago, the insurance company began coordinating Family and Parents Night across its local offices, inviting interns' parents in to see where their children work. Michael Van Grinsven, who directs the company's field internship program, says millennials' mothers and fathers have played such a role in mentoring them professionally that "what we decided to do was embrace it."

Fighting parents' involvement, he says, would have been worse. "If we'd been resistant to it, they might have been resistant to their sons or daughters even joining us." Now, the company has found ways to maintain that family involvement even after those interns become employees. Parents can receive e-newsletters that share updates about their kids' work. They are also sometimes invited to recognition dinners.

"People used to say: Wait until [millennials] get to the workplace, the workplace is going to change them," Van Grinsven says. "But the workplace is responding to them."

College costs and economic trends also may have played a role in thawing the relationship between employers and parents. Given Americans' increasing anxiety about student debt, the high unemployment rate for millennials and the record number of twenty-somethings living at home, it's little wonder families want to know more about the career prospects for their children.

"If you're living with your parents and you're going to work, you’re more prone to your parents being more involved," says Dan Schawbel, the managing partner of a generational research and consulting firm. The economy, he says, has "forced delayed adulthood."

Plus, at perk-filled campuses like LinkedIn and Google, where employees can eat all their meals and drop off their dry cleaning, work and home have become inextricably intertwined. "It's more blended, it's more casual," Schawbel says. "They want your life to be at the company rather than outside. One of the ways they pull that off is to bring employees' parents — the most influential stakeholders in their lives — into the workplace."

Danielle Restivo, who oversees global public relations programs for LinkedIn, says the idea for the company's event came in part from an email she got from her own mother. It said: "I'm proud of you and love you, but I have a hard time explaining what it is that you do," Restivo recalls. Her mom wanted a note, complete with simple bullet points, that she could carry around in her purse. That's when Restivo and her team dreamed up LinkedIn's Bring In Your Parents Day, which last year played host to about 600 parents globally at the company.

The event included talks by executives and employees about what LinkedIn does, how it makes money and what a typical workday is like. "We got a lot of tough questions," Restivo says, such as: "How do we know this isn't just a flash in the pan?" And, like David Henderson's mother, parents got a taste of the free food along with the company culture. As Joe Hirz, a retired auto mechanic whose daughter works at LinkedIn, said of his visit to the Silicon Valley company: "It was like being on a cruise ship."

According to the Society for Human Resource Management, only 1 percent of U.S. companies currently host such events. Yet this isn't just a budding American phenomenon. At Google and Starbucks, the program actually began overseas — Google held its first parents day in 2012 in Hyderabad, India, and Starbucks did the same that year in Beijing and Shanghai, China.

In both countries, parents are more accustomed to having a hand in their children's professional lives. According to 2013 data from PricewaterhouseCoopers, for instance, just two percent of U.S. college graduates think it's a good idea for parents to receive a copy of their performance reviews, compared with nearly 24 percent of grads in India.

It was a U.S.-based employee working at Google in India who suggested importing something like the Hyderabad event to the company's American workforce. Now, parents here can not only visit Google's campus — they have the option of sitting down solo with their child's manager. Meghan Casserly, a Google spokeswoman, is quick to say it's very rare for parents to take the company up on that offer, however. "I think managers are actually thankful," she says. "They can keep their workday going."

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