Plays a major role in controlling sexual cell fates. Promotes female development in XX animals where it sequesters one or more of the FEM proteins to the membrane thereby freeing the tra-1 protein (a putative transcription factor) to enter the nucleus and promote female development. In XO animals it acts as a receptor for her-1 which prevents it from binding to FEM proteins thereby repressing the activity of tra-1. Negatively regulates male development when bound to fem-3 and is required together with tra-1 for promoting spermatogenesis. Also required for feminizing tra-3 activity. Interacts with tra-1 and fem-3. Somatic and germline tissues. Isoform Tra-2B is specific to oocytes. Expressed both maternally and zygotically. Undergoes cleavage by tra-3 to produce a feminizing carboxy-terminal isoform Tra-2B. Isoform Tra-2B is likely to be cytoplasmic because it lacks an N-terminal sequence and potential membrane spanning domains. The MX region mediates a post-translational regulation, essential for the onset of hermaphrodite spermatogenesis. Produced by alternative initiation at Met-1089 of isoform Tra-2A.