![sperm](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2016/05/042916_ss_sperm-beads.jpg?fit=860%2C460&ssl=1)
BOUND Mouse sperm (left, red) flock to a polymer bead coated with the sperm-binding sections of a protein found around unfertilized eggs (illustration, right). Such beads could someday be used as contraceptives or a method for identifying healthy sperm, researchers report.
M.A. Avella et al/STM 2016