We have studied data that emerged in the analyses of male adult twins. As a result we have identified certain patterns of phallic aggression in twins and particular solutions to conflicts arising from this aggression. These patterns are consequent to competition between them for the birthright, the preferred position, and identification with the parent. Solutions to these conflicts include shifts between active and passive, feminine and masculine,

and phallic and receptive positions both in the characterological sense and in the phallic-active and the phallic-receptive sense. These shifts often involve an inhibition of phallic aggression and assertiveness by the potentially stronger twin.