Carrier females and sender males: An evolutionary hypothesis linking female attractiveness, family resemblance, and paternity confidence

The article introduces and elaborates the hypothesis of carrier features, characteristics which in females are attractive to males as mate-choice cues. Female carrier features increase paternal resemblance and are ultimately attractive because they help pair-bonded males distinguish genetic offspring from those conceived by mates in extra-pair copulations. The proposed kin recognition mechanism, whether culturally evolved or innate, facilitates discriminatory paternal investment, and hence male fitness. Carrier features would be attractive to males in monogamous species where paternal investment is high, and cuckoldry represents a significant risk to male fitness. Logical space exists for male sender features, which tend to be expressed in offspring regardless of female characteristics. Conflict of genetic interests between the sexes should favor the evolution of carrier, rather than sender, features in both sexes. The argument centers on humans, for whom candidate carrier features are discussed with regard to physiognomy, behavior, recessive traits, and body odor. Criticisms are discussed, and testable predictions enumerated.