阿历斯（阿诺•施瓦辛格 Arnold Schwarzenegger 饰）和拉里博士（丹尼•德维托 Danny DeVito 饰）研究了一种新的生育配方――安胎灵，它能大大降低女性怀孕的风险。但这种药却没有获得联邦药物处的人体试验批准，所以一直不能上市。资助方将资金和设备都抽走了，无奈两位博士被竞争对手兼顶头上司诺亚安置到女博士黛安娜（艾玛•汤普森 Emma Thompson 饰）手下协助工作。拉里博士为了他们的产品能顺利上市，偷偷将黛安娜冷藏在实验室准备做实验用的卵子和阿历斯的精子结合成受精卵，并劝服了阿历斯在体内植入受精卵，这下，世界上第一例男人受孕就诞生了！ 阿历斯开始服用他们的产品安胎灵，他们打算在胎儿3个月的时候就将其取出。然而，随着阿历斯服用的安胎灵越多，他各方面都开始出现女性的特征，而且，他开始决心要将胎儿生下来……
Alex Hesse (Arnold Schwarzenegger) and Larry Arbogast (Danny DeVito) are working on a new drug which will reduce the chances of a woman's body rejecting her baby, and thus causing a miscarriage. When their research funding is withdrawn, and human experimentation is denied to them, they decide to test the drug by briefly impregnating Hesse. However, Hesse becomes attached to his unborn baby.
