Orphan Black is one of the most intelligent, nuanced, and ambitious shows on television, thanks in no small part to the contributions of science consultant Cosima Herter. Recently, she wrote an essay dealing with the nature vs. nurture debate, and it's fantastic.
In her essay "Variability and Perturbations of the Spiral Universe Inside Us," which title mimics that of the most recent episode of Orphan Black, Herter examines the balance between agency and fatalism in our modern understanding of human genetics, contrasting that understanding with an improbable analog – astrology – to argue what many will no doubt regard as a contentious point: That "genetics is not a synonym for determinism any more than astrology is."
Her ultimate argument, that sexuality cannot be distilled to so simple a comparison as "nature vs nurture" is less contentious:
But, insofar as sexuality has a genetic component (like all biological characteristics) it is not so simply explained by genetics alone. Moreover, it is not regulated by any one single gene. Despite how studies on the genetics of sexuality are represented in the popular press that either decry or redeem the genetic basis of sexual orientation, none of the research to date that espouses to have found the "gay-gene" (or, more recently the "male-loving gene") are actually supported by a claim that one gene, and one gene alone, determines sexual orientation. Sexuality is complex, both as a biological component and a political identity. Our genes do not define who we are, and while certain genes may indeed be present, they may or may not be expressed depending on a whole spectrum of environmental and biological circumstances. The reductionism of either 'nature' or 'nurture' is far from adequate to explain sexuality.
You can read the full essay at the BBC America's Writers' Blog.