FORT LAUDERDALE, Fla. — The stabilizing housing market is becoming a curse for first-time homebuyers.

Despite affordable prices and historically low mortgage rates, these buyers are being shut out of the market by strict lending standards and a dearth of homes for sale. When they do find a place, it’s also targeted by investors whose cash offers make sellers swoon.

Ally Apostolis and her boyfriend, Steve Momot, have been looking for a home since March. They found the perfect place, a three-bedroom in Fort Lauderdale for $149,000. They bid just above the list price but still lost the home to a cash buyer.

Late one night, Apostolis found another home she liked, but it already was off the market by the next morning. She and Momot recently made yet another offer that the seller accepted, but it’s a short sale, which requires lender approval, so the deal could still take weeks or months.

“We’ve had a rough time,” said Apostolis, 26, an executive assistant for an oil hedging firm. “If this doesn’t work out, it’s going to be a stressful road ahead of us.”

First-time buyers are considered the backbone of the nation’s housing market. When young, single professionals or newly married couples buy and furnish homes, the ripple effect stimulates the economy. Traditionally, these buyers use the profits from the sales of first homes to buy bigger properties, creating a confidence that typically sustains the market for years to come.

“You constantly need a fresh crop of first-time buyers coming in to an area to a have a healthy housing market,” said Greg McBride, senior financial analyst with Bankrate.com in North Palm Beach, Fla.

“Without the starter home market, you don’t have a recovery,” said Lewis Goodkin, a housing consultant based in Miami.

First-time buyers accounted for roughly a third of all home sales nationwide in May, according to the National Association of Realtors. Ideally, the percentage should be 40 percent or more, said Walter Molony, a spokesman for the Realtor trade group.

State and local Realtor boards say they don’t yet track numbers of first-time buyers. But more than six out of 10 sales in May across Palm Beach and Broward counties were cash deals, well above the national average, according to the Miami Association of Realtors.

Almost all first-time buyers need financing, which has been difficult to get following the housing boom. Many first-time buyers prefer Federal Housing Administration loans because they require only 3.5 percent down payments.

But sellers worry that FHA deals will fall apart, real estate agents say. The government insists that FHA-eligible homes be in good condition, requiring sellers to make repairs, such as replacing rotted wood and installing a working pool pump.

Because sellers, including banks, don’t want the hassle and expense, they prefer to deal with cash buyers - many of them investors from Canada, Brazil and other countries who see American real estate as a sound investment. They buy the homes as-is and the deals tend to close quickly.

“It’s not just the highest offer, it’s the highest and best, and many times that’s a cash transaction,” said Marta DuPree, an agent for Keyes Co. in Florida’s Broward and Palm Beach counties.

Today’s first-time buyers also face a shortage of available homes. Recent price increases have persuaded some homeowners to hold off selling until values rise even more. Other owners can’t sell because they owe more than their homes are worth.

To compete in a tight market, first-time buyers should be preapproved by a lender for a specific mortgage amount so they can act quickly the moment a home is listed for sale, real estate agents say.

Also, buyers may want to consider conventional mortgages instead of FHA loans. Conventional mortgages require a little more down - 5 percent - but they’re seen as more attractive than FHA, said Stephen B. McWilliam, president of the Greater Fort Lauderdale Realtors.

“The sellers know there’s less red tape with conventional,” McWilliam said.

Judy Trudel, an agent in Lighthouse Point, Fla., said she tells first-time buyers the process may be more difficult than they expect.

“I say, ’Don’t get your hopes up,’ ” Trudel said. “But it generally doesn’t sink in until they’ve lost a couple of houses.”

Christian Montalto of Hollywood, Fla., knows the feeling.

The high school English teacher has been looking for a two-bedroom home in Broward County since last fall. He says he has made at least 10 offers, to no avail.

Either investors out-maneuver him or he kills the deals himself because sellers aren’t willing to make the necessary repairs. Montalto, 30, never thought it would be this “cutthroat,” but he perseveres.

“The Red Sox won the World Series,” he said, “so anything’s possible.”