Mother told you to never look a gift horse in the mouth. Ignore that advice when a gift of money is offered from a down payment assistance program. Check whether the nonprofit program is legitimate and whether accepting the money is in your best interest.

Each month, more than 15,000 home buyers use such programs to make down payments while qualifying for mortgages insured by the Federal Housing Administration. That amounts to almost 1 in 5 FHA borrowers.

The programs offer a way for buyers to qualify for mortgages when they earn enough to make the monthly loan payments but can't save enough for a down payment. It works like this: The seller gives money to a nonprofit down payment assistance program. The program then gives a similar amount to the home's buyer when the loan closes, and the gift is treated as a down payment. The amount typically is 3 percent to 6 percent.

A middleman is necessary because lenders don't allow home sellers to give down-payment money directly to buyers. But under rules governing FHA loans, borrowers can accept down payment money from charities. This loophole gave rise to down payment assistance programs, which have abandoned the pretense of charity and have embraced their role as facilitators of the home-buying process for low-income and minority families.

Down payment assistance programs have joined the mainstream. But not all of the programs are equal.

An unknown number of borrowers found that out the hard way last spring, when the federal Department of Housing and Urban Development barred a down payment provider from doing any business connected with FHA loans for a year. According to a HUD spokesman, Florida-based Affordable Housing Concepts lied to a lender and to the public that it was HUD-approved.

How can you avoid questionable providers? Try dealing with nonprofits that belong to the Homeownership Alliance of Nonprofit Downpayment Providers. It has a set of best practices and a code of ethics, and it lobbies Congress and HUD on behalf of its members. A list of member companies is posted on HAND's Web site. You also might ask about the nonprofit's financial stability.