by Jamie Henzy — Is there any deny­ing that preg­nancy is a form of par­a­sitism? The de­vel­op­ing or­gan­ism orig­i­nates at least in part from out­side the host (in sex­u­ally re­pro­duc­ing crea­tures, at least), and me­di­ates the rerout­ing of nu­tri­ent sup­plies at the host's ex­pense. In the case of mam­mals (and many other classes), where the...