Spock's backstory has been explained during the course of several episodes of ', the 2009 film "Star Trek" and the episode "" of '. Spock was born to the Vulcan Sarek and the human Amanda Grayson. Due to this mixed-species heritage, Spock had to be removed from Amanda's body and raised in a test tube for two months, during which time Vulcan scientists made subtle chemical adjustments to the fetus to ensure its survival. The fetus was returned to Amanda's body to complete the human gestation period, then put in an incubator for four months to complete Vulcan gestation. He is the first such mixed-species child to survive.