Slow sperm may fail at crashing ‘gates’ on their way to an egg
Narrow spots in the female reproductive tract could help weed out less desirable suitors
SWIM MEET Sperm face many obstacles along the way to an egg, including narrow points in the female reproductive tract that help sort out the top swimmers.
Panther Media GmbH/Alamy Stock Photo
The female reproductive tract is an obstacle course that favors agile sperm.