First-time Homebuyer Affordability Act of 1999

First-time Homebuyer Affordability Act of 1999 - Amends the Internal Revenue Code to make the tax on prohibited transactions inapplicable to a qualified home equity participation arrangement (one in which up to $10,000 in an individual retirement plan is used to acquire an ownership interest in a dwelling unit that is to be used as the principal residence for a first-time homebuyer). Requires such ownership interest to be a fee interest requiring full repayment. Defines "first-time homebuyer" as an individual on whose behalf an individual retirement plan is established (eligible participant) or a family member (child, parent, or grandparent) who had no present ownership interest in a principal residence during the 36-month period before the date of the arrangement.

Allows the use of amounts in an individual retirement plan to make loans of up to $10,000 to purchase a home for a first-time homebuyer on behalf of an eligible participant or a family member. Prohibits a related interest deduction. Requires repayment within 15 years.