在这部胎记喜剧片中,天性与后天的培养究竟哪个更重要？本·莫林和妻子凯瑟琳·奥尼尔都是备受尊敬的科学家，两人进行了一项他们认为能改变人类对自己身份认知的实验：用与三个孩子遗传的天性相悖的方式抚养他们，最终证明后天对孩子的抚养可以胜过孩子先天的天性。他们希望证明人都具备达成任何成就的潜能。本和凯瑟琳在实验中发现了家庭的可贵，比起实验的科学真相，后者微不足道。
In 1977, two respected scientists, Ben Morin and his wife Catherine quit their jobs at the university to conduct an experiment they think will revolutionize our understanding of human identity. The project aims to raise three children contrarily to their genetic predispositions to prove the ultimate power of nurture over nature. They want to prove that everyone has the same potential to become anything. Maya, a newborn girl adopted from two feebleminded parents, is raised to be smart, while Maurice, a newborn boy adopted from two anger-prone parents, is raised to be a pacifist. Finally, their own biological son Luke, who comes from a long lineage of scientific brains, is raised to become a revered artist. The experiment will reveal little scientific truth, but rather lead Ben and Catherine to discover the true value of family.
