[Risks and benefits of genetic screening: the sickle cell trait as a model in a Brazilian population group].

Population screening of asymptomatic heterozygotes for genetic guidance purposes is a very controversial procedure due to the risk of labeling, discrimination, stigmatization, loss of self-esteem, and invasion of privacy. Effects of genetic counseling supplied to blood donors with the sickle cell trait (AS heterozygotes) were investigated. Ninety-two AS donors were invited by letter to a free, individual orientation session; 66 of them (72%) accepted the invitation. Some 50% of the individuals brought their wives and children for examination, thus allowing identification of several at-risk couples (13%) and children with sickle cell anemia (5%). Six months afterwards 43 AS donors (65%) were reevaluated, whereby it was observed that the information had been well assimilated. The theoretical risks of genetic screening did not appear to be cause for concern in most of the cases examined. However, signs of stigma, labeling, discrimination, loss of self-esteem, and invasion of privacy were evidenced in a few cases.