Their high pay is just child’s play.

Though tech workers in the Bay Area make an average of $147,000 a year, many say they can’t afford to have kids, according to a new survey of more than 8,200 people by Blind, a workplace social network used primarily by tech workers many of whom are in the Bay Area. Indeed, 58% answered “yes” when asked if they’d put off having children due to the cost.

What’s more, data released earlier this year by real estate firm Zillow bolsters this conclusion: “Birth rates are dropping the most in countries with the fastest-appreciating home values,” the report reveals. “The trend is most pronounced in pricey California markets.” On average, when an extra 10 percentage-point rise in home values is associated with an extra 1.5 percentage-point drop in birth rates for 25-to-29 year old women.

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In the Bay Area, the problem is particularly pronounced: In San Jose, the birth rate among this age group has fallen 20% from 2010 – 2016, Zillow reveals. And in Oakland it’s fallen 24%.

No doubt, people realize that raising kids is pricey. The average cost to raise a child in America is $233,610, according to government data — and that doesn’t include the cost of college. In San Francisco, that number is roughly double that.

“Raising a child is an expensive proposition, and many couples may be questioning whether now is the right time to have kids or may be choosing to move to more affordable communities before starting a family,” the Zillow report concluded. “Many young adults aim for financial stability before having children, but with rising housing costs, financial stability may be increasingly out of reach.”

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And when you add in the cost of real estate — which ranges from $747,000 for the median home in Oakland to nearly $1.4 million in San Francisco — and cost of living that’s about 50% or more above average, you can see why some workers may be putting off having kids.