Teen-age pregnancies cost the American taxpayers about $8.3 billion a year in welfare and related outlays, according to a new study by Stanford Research Institute.

Although welfare experts have long suspected that the nation's 600,000 annual births to teen-aged girls produce massive welfare costs for the federal, state and local governments, the Stanford study is the first to come up with a specific figure.

The $8.3 billion includes all cash support payments, food stamps, social services, free medical services and related welfare outlays by the federal, state and local governments to house-holds containing teen-aged mothers or women who first became pregnant in their teens [WORDS ILLEGIBLE] director of the study for Stanford (SRI International), said the total would be $1.5 billion higher if abortion were to become illegal or if state financing of abortions for teen-agers were to cease.

The $8.3 billion total calculated by Robbins is higher than the budgets of many countries, such as New Zealand or Portugal, and some Latin American nations. It is higher than the total 1979 budgets of many federal departments like Commerce, Interior and State - and only a bit lower than the budget of the Energy or Housing and Urban Development departments.

The SRI study, commissioned by the Population Resource Center, said a "disproportionate number of [teen-aged] mothers come from poor families; unable to give them financial support." As a result, many (more than a third are unmarried at the time of the baby's birth) eventually end up on [WORD ILLEGIBLE] .

The SRI International figures were computed by calculating in 1979 dollars the longterm welfare costs to be expected for girls having their first child as a teen-ager in 1979.

Robbins calculated that over the first 20 years of the life of each child, the total welfare costs for support of these girls and their children (excluding medical care) would be about $7.1 billion. Medical care would add another $1.2 billion for a total of about $8.3 billion.

Thus, each year's batch of teen-aged mothers (assuming the same total number of births) ultimately costs the U.S., state and local government $8.3 billion. At any given time, there are 20 batches on welfare.

This means, said Robbins putting the figure in a different formulation that teen-age pregnancy costs the tax-payer about [WORDS ILLEGIBLE]