Self-organisation of testosteron level in Penna-Klotz ageing model

Summ. We assume that insufficient testosteron in males leads to a reduced n umber of surviving offspring, and follow Klotz that testosteron diminishes the survival probability of males compared to females. Then simulation of t he Penna model of biological ageing shows self-organization of an intermedi ate level of testosteron, with realistic differences between male and femal e mortality.