Magnetic-activated cell sorting (MACS) is a method for separating various cell populations based on their surface antigens. This technique has been applied in assisted reproduction hospitals to sort out sperm with fragmented DNA using antibodies to surface markers of programmed cell death (apoptosis) such as annexin V, coupled with magnetic beads. The MACS process involves the use of very small biodegradable magnetic particles that fasten themselves to sperms with high DNA fragmentation, that are more likely to undergo apoptosis or programmed cell death. MACS is a novel sperm preparation technique that separates apoptotic and non-apoptotic spermatozoa based on the expression of phosphatidylserine.

The incorporation of MACS as a sperm preparation technique has led to improved outcomes in assisted reproductive techniques (ART).