Casanovas A, et al. - Researchers undertook an observational, double blind, prospective cohort study to determine the effect of single- and double-stranded sperm DNA fragmentation (ssSDF and dsSDF) on human embryo kinetics monitored under a time-lapse system. They prospectively included 1 hundred ninety-six embryos from 43 infertile couples to analyze SsSDF and dsSDF in the same semen sample used for intracytoplasmic sperm injection. Then, using time-lapse technology, they monitored embryo kinetics and obtained the timing of each embryo division. A delay in embryo development and impairment in implantation were observed in correlation with double-stranded sperm DNA damage, however, embryo kinetics and implantation were not significantly affected in correlation with single-stranded DNA damage.