Cohn, who’s based at the University of Florida, studies genitals and urinary tracts, and how they develop in embryos. Around 1 in 250 people are born with birth defects affecting these organs, and although such changes are becoming more common, their causes are largely unclear. By studying how genitals normally develop, Cohn’s hoping to understand what happens when they take a different path. And like many scientists, he is working with mice. He recently analysed a mouse’s genitals with a high-resolution medical scanner. To show his colleagues how incredibly detailed the scans can be, he used them to print a scaled-up model, which he took with him to the conference in DC. And because the conference was just a two-day affair, Cohn didn’t bring any checked luggage. Hence: the penis in his carry-on.

Scientists, as it happens, are full of tales like this because as a group, they’re likely to (a) travel frequently, and (b) carry really weird shit in their bags.

In previous years, Cohn has flown with the shin bone of a giant ground sloth and a cooler full of turtle embryos. Just last month, Diane Kelly from the University of Massachusetts, who studies the evolution of animal genitals, was stopped by the TSA because she was carrying what is roughly the opposite of Cohn’s item: a 3-D-printed mold of a dolphin vagina. “Technically it’s not even my dolphin vagina mold,” she says. “I was carrying it for someone.”