Lillian Kasparian, age 16, of Asbury Park, N.J., for her question:

CAN YOU EXPLAIN ENDOGAMY?

Endogamy, in the social sciences, is a term applied to customs prevailing in certain societies whereby a member of a community, clan or other social unit is forbidden to marry a member of a different social unit.

Endogamy practices may be based on caste, as among the Hindus of India; on occupation, as among the Masai of east Africa; on age group, as among the Australian aborgines; on genealogical descent, as among Europcan royalty; or on economic and social status, as among the upper classes of many nations.

The most restricted form of endogamy was that practiced by certain rulers of ancient Egypt, who were expected to maintain the purity of the royal blood by marrying within their families. Authorities differ as to the advantages and disadvantages of endogamy as a device for the perservation of allegedly superior or aristocratic bloodlines with many saying that inbreeding is likely to cause a degeneration of the stock.

Many scientists against endogamy say that intermarriage among races has often produced types that combine the best elements of the two parent races and are often superior to both.