The Science Behind Our Tests

What causes damage to sperm DNA?

Damage to sperm DNA is mostly caused by oxidative stress via free radicals.  Free radicals attack the DNA resulting in single or double-strand breaks in the DNA molecule itself, which produce single or double-stranded DNA fragments (Figure 1).

Sperm do not have the cellular machinery to repair DNA damage so even men who are dads have some damage in their sperm.  The amount of damage caused can vary from one individual sperm to another.

However, once the total average damage reaches a certain level it can cause fertility problems.

Sperm DNA Single-Strand DNA Breaks (ssDB) vs. Double-Strand DNA Breaks (dsDB)

Free radicals cause more ssDB in sperm DNA because it is highly susceptible to oxidative damage due to its dense packing and the presence of fewer DNA repair mechanisms compared to other cell types.

dsDB are less common but highly significant because they are particularly detrimental to sperm DNA integrity. Double-strand breaks occur when two single-strand breaks happen close to each other on opposite strands, or when a single-strand break is converted into a double-strand break due to incomplete repair.

Consequently, while single-strand breaks are more common, double-strand breaks, though less frequent, can be particularly harmful to sperm DNA integrity and overall fertility.

Examen’s world-leading SDF tests are able to measure total SDF damage, and uniquely, can also specifically measure dsDB fragmentation damage only.