Elevated temperatures negatively affect human reproduction through several processes that regulate nutrient uptake and resource allocation in pregnant women. These can interfere with foetal development, resulting in low birth weight neonates with altered development trajectories. Temperatures that affect the current generation could, therefore, also have an impact on the following generation. We asked whether heat stress affected offspring fertility by asking if current and past ambient temperatures influenced total fertility rates (TFR) in human populations distributed across the world. We analysed time series data in 65 countries using simple regression analyses based on maximum temperatures and temperature amplitudes over 55 years. Supplemental longer time series (up to 100 years) provided information on response patterns in Northern Europe and Greenland’s colder climates. There were clear and strong effects of temperatures on the TFR in the concurrent and the previous generation. Our temperature-based models account for 71–95% of the variation in TRF in European countries and Greenland, and 56–99% of the variation in 65 countries worldwide. Our findings are consistent with studies of seasonal variation in fertility and suggest that increased temperatures will negatively influence populations subjected to monthly maximum temperatures above 15–20 °C, while fertility in colder climates benefits from elevated temperatures. Our results provide strong evidence that ambient temperatures have important effects on human fertility, and that these effects persist into the following generation.

升高的温度通过调节孕妇营养吸收和资源分配的几个过程对人类繁殖产生负面影响。这些会干扰胎儿发育，导致低出生体重新生儿的发育轨迹发生改变。因此，影响当前一代的温度也可能对下一代产生影响。我们通过询问当前和过去的环境温度是否影响分布在世界各地的人口的总生育率 (TFR) 来询问热应激是否影响后代生育率。我们使用基于 55 年最高温度和温度幅度的简单回归分析分析了 65 个国家/地区的时间序列数据。补充的较长时间序列（长达 100 年）提供了有关北欧和格陵兰较冷气候的响应模式的信息。温度对同时代和上一代的 TFR 有明显而强烈的影响。我们基于温度的模型占欧洲国家和格陵兰 TRF 变化的 71-95%，占全球 65 个国家的 56-99%。我们的研究结果与生育率季节性变化的研究一致，并表明温度升高将对每月最高温度超过 15-20 °C 的人群产生负面影响，而较冷气候下的生育率则受益于升高的温度。我们的结果提供了强有力的证据，表明环境温度对人类生育能力有重要影响，