Silicon Valley is an industry whose foundation was built, byte by byte, with youthful innovation.

Look no further than some of tech’s greatest minds for proof. Steve Jobs and Steve Wozniak were 21 and 25 when they co-founded Apple (AAPL). Sergey Brin and Larry Page were twenty-something Stanford University graduate students when they built the search engine that became Google (GOOG, GOOGL) in the garage of a home in Menlo Park, Calif.

And Mark Zuckerberg dropped out of Harvard University to pursue and develop Facebook (FB) — a move Peter Thiel likely appreciates, given the billionaire tech investor offers the Thiel Fellowship, a two-year program that rewards select fellows who are 22 or younger with cash to drop out of (or take a leave of absence from) college to pursue and develop tech ideas.

While tech often reveres youth, the opposite can be true. Movies like “The Intern” and “The Internship” mock the notion of ageism in tech, but for some people in the real world, being over 40 (or even 30) can be a real liability. That may be because of a fast-paced work environment that can shift on a dime, or because older people are frequently associated with being familiar with older technologies. And while it’s illegal to discriminate against workers over 40, such cases can ultimately be difficult to prove.

“This is not an area where anyone values past experiences much, and there is logic to that: things change too fast,” says Steve, a 43-year-old software engineer at a consumer-focused startup in San Francisco, who asked that we not use his real name out of concern for his privacy.

The numbers show that tech is an unusually young industry. The median age for the typical US worker is 42, according to the US Bureau of Labor Statistics, but in tech, workers are frequently a decade younger (or more). To wit, data compiled from salary firm PayScale, which compared data in 2016 from 18 different tech employers, revealed the median age of workers at companies such as Facebook, LinkedIn and SpaceX is 29, with only three companies — IBM (IBM), Oracle (ORCL) and HP (HPQ) — reporting a median employee age over 33.

For “older” employees who do land tech gigs, youthful workplaces can provide social challenges. In an attempt to blend into his employer’s work culture, where many of his colleagues are in their 20s, Steve tries to look and dress younger, dying his hair to cover up gray and slathering on a slew of anti-aging skin products — “anything with retinol,” he explains — to look more youthful. He even stays on top of the latest trends in entertainment so he can chat about movies and music with his millennial colleagues over lunch or beers.

The data supports Steve’s concerns about fitting in. According to a tech salaries report released this month from Hired, a San Francisco-based tech worker recruiting firm, candidates seeking tech jobs between the ages of 25 and 30 receive the highest number of average job offers.

Once candidates pass the age of 45, the average tech worker salary and average number of job offers starts going downhill. Tech companies on average offer $132,000 to candidates between the ages of 50 and 60, comparable to what employers offer candidates at least 10 years junior, and who presumably, have at least 10 years less of work experience.

“There are a variety of factors that could contribute to this trend, but we see this as an example of unconscious biases hurting the hiring process,” Hired data scientist Jessica Kirkpatrick, who authored the report, told Yahoo Finance. “Some hiring managers may not realize that they naturally prefer younger candidates for culture fit reasons, but their bias during the interview process can have a lasting impact. Different ages bring new experiences and ways of thinking to the table and should be considered a standard part of any company’s commitment to diversity. ”

Kirkpatrick based her “ageism”-related findings on salary data gathered from over 280,000 interview requests and jobs offers over the last 12 months from over 45,000 job seekers in 16 cities, including San Francisco and New York.

The youthful tech culture is a real concern for tech workers like Anne, a 38-year-old project manager at a San Francisco startup who also declined to have her real name used for privacy reasons. Having worked at several tech companies over the last 10 years, Anne is already considering a career change. Her reasoning, put simply: she feels like she’s “aging” out of the industry already.

The startup she currently works at does not offer what she considers family-friendly policies. For example, her employer offers just six weeks of paid maternity leave on top of two months of unpaid leave, which the company can currently get away with given the majority of Anne’s colleagues are in their 20s and likely less focused on having families.

“It’s hard to connect with people around you every day when you’re more concerned about health plans and maternity leave policies, and your coworkers are more worried about which bar to have happy hour at,” explained Anne, who is trying to have her first baby with her partner.

Some tech companies, to be fair, are making efforts to provide better benefits that might appeal to workers over the age of 30. Facebook, for example, has made significant strides thanks to Zuckerberg himself, who famously took two months of paternity leave in late 2016 and early 2017 to spend time with newborn daughter Max. The chief executive’s move spurred Facebook to offer four months of “paid baby leave” to all Facebook employees, regardless of gender or location.

That may be little comfort to middle-aged tech workers who can’t snag a job at more inclusive businesses, though.

David, a 40-year-old unemployed user experience designer, has interviewed at over a dozen San Francisco startups for jobs over the last two months, but hasn’t received an offer yet. He attributes part of the challenge to simply looking significantly older than the 20-something founders and CEOs who interview him.

“I was thinking I should maybe change my hair and shave my beard to look younger,” David wonders. “What do you think?”

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JP Mangalindan is a senior correspondent for Yahoo Finance covering the intersection of tech and business. Follow him on Twitter or Facebook.

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