The matrilineal Trobriand Islanders recognize the importance of sex in reproduction .
The matrilineal Trobriand Islanders do not believe the male makes a contribution to the constitution of the child , who therefore remains attached to their mother 's lineage alone .
The matrilineal Trobriand Islanders recognize the importance of sex in reproduction but do not believe the male makes a contribution to the constitution of the child , who therefore remains attached to their mother 's lineage alone .