Imagine turning one of nature’s fastest swimmers into a precision medical tool. Researchers have transformed real sperm cells into “sperm bots” by coating them with magnetic nanoparticles, creating microrobots that can be steered from outside the body and watched in real time with X-rays. Reported in npj Robotics, the work bridges biology and engineering to tackle problems that standard imaging and drug delivery can’t reach.⁠ ⁠ Sperm are naturally agile, biodegradable couriers built to navigate the complex terrain of the female reproductive tract. With their magnetic coats, these cells became both visible and controllable inside a life-sized anatomical model, traveling from a mock cervix through the uterine cavity toward the fallopian tubes. That level of guided motion, paired with continuous tracking, offers a view of reproductive transport scientists have never had.⁠ ⁠ The clinical promise is targeted therapy. Instead of bathing tissues in systemic drugs, clinicians could one day loa...