Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Semen parameter definitions for childhood mortality risk in men undergoing SA versus fertile men. Morphology was categorized into equally distributed quartiles (Q) because the World Health Organization threshold for normal motility changed multiple times during the study period.
