Yet at the dawn of the 21st century, humanity’s growth has noticeably slowed, and the change seems to be a trend, not an anomaly. Much to the dismay of fanciful futurists like Ray Kurzweil, who envision humans living 200 years or more, our species shows no signs of pressing forward to to new biological heights without serious technological intervention. Instead, we are plateauing.

Last year, in the journal Frontiers in Physiology, Adrien Marck and a team of researchers at the Institute of Biomedical Research and Epidemiology of Sport in France, laid out a strong case that humanity may be nearing its biological limits.

“It is now possible to ascertain the biological limits of the human species, through sport records, lifespan, or height,” they wrote. “These traits no longer increase, despite further continuous nutritional, medical, and scientific progress. This suggests that modern societies have allowed our species to reach its limits. We are the first generation to become aware of these limitations.”