The human brain is not a single organ, but two separate systems that evolved independently before fusing together, according to groundbreaking new research. … Armed with the knowledge of how hindbrain cells uniquely form, the team has successfully turned human stem cells into becoming functional hindbrain motor neurons in a lab for the first time.
I believe they were making a joke about different positions of intercourse, not actually answering the question. e.g. “Front” ≈ missionary on a normal day, and “hind” ≈ doggy when frisky.