Text: Rather it may serve to delay the conception of a rival for maternal resources--both directly (by literally coming between Mom and Dad) and indirectly (by tending to prolong breast-feeding and, therefore, to suppress ovulation for a longer period).
Entailment: It may serve to delay, directly or indirectly the conception of a rival for maternal resources.
Contradiction: It is useless to delay, directly or indirectly the conception of a rival for maternal resources.