Greetings from a Triparental Planet

In this work of speculative science, scientists from a distant star system explain the emergence and consequences of triparentalism, when three individuals are required for sexual reproduction, which is the standard form of mating on their home world. The report details the evolution of their reproductive system--that is, the conditions under which triparentalism and three self-avoiding mating types emerged as advantageous strategies for sexual reproduction. It also provides an overview of the biological consequences of triparental reproduction with three mating types, including the genetic mechanisms of triparental reproduction, asymmetries between the three mating types, and infection dynamics arising from their different mode of sexual reproduction. The report finishes by discussing how central aspects of their society, such as short-lasting unions among individuals and the rise of a monoculture, might have arisen as a result of their triparental system.