In the present study, blood pressure, the renin angiotensin aldosterone system, and other cardiovascular risk factors, such as glucose, cholesterine, and triglycerides, were investigated in 294 offspring of essential hypertensives (5-34 years) and in 122 children of normotensive parents (5-34 years). Offspring of essential hypertensives showed statistically significant higher systolic and diastolic blood pressure values than those of normotensive parents (p less than 0.003, less than 0.005, respectively). Furthermore, in children of hypertensive parents a statistically significant higher body weight and body mass index than in controls could be observed (p less than 0.006, less than 0.001, respectively). With the exception of statistically significant, lower mean supine plasma aldosterone values (p less than 0.02) in children of hypertensive parents, no major differences between the two groups were seen in stimulated aldosterone, supine and stimulated plasma renin activity, and plasma cortisol. Furthermore, in the present study, 41 hypertensive parents, 65 (normotensive) spouses of hypertensives, and 47 (normotensive) parents of control children were investigated. As expected, hypertensive parents showed statistically significant higher blood pressure values than parents of control children and their spouses (p less than 0.001). Interestingly, hypertensive parents had not only a higher body mass index than control parents but also than their spouses (p less than 0.01 and less than 0.02, respectively). These findings support a genetic disposition as being the underlying cause of higher body weight in hypertensives and make it less probable that a higher food intake in hypertensive families is responsible for this phenomenon. The results of the present study indicate that early body weight control in children of hypertensive parents may be an important contribution to the prevention of hypertension.