It’s not uncommon to find abnormal sperm among other healthy sperm; in fact, it’s quite common to have a percentage of abnormal sperm present in the sperm count, and, should pregnancy occur, these abnormal sperm pose no risk to the fetus or increase the risk of birth defects.
A normal sperm has an oval head and a tail. Abnormal sperm have head or tail defects, including misshapen heads, or double or crooked tails. An andrologist can determine the percentages of normal, undetermined and infertile sperm present in each sperm count. Though it varies from clinic to clinic, a “normal” count has more than 14% healthy sperm, an “undetermined” diagnosis occurs when healthy sperm make up 7-14% of the sample, and a patient is classified as “infertile” when his healthy sperm is counted as less than 6%.
However, these numbers are not set in stone, as everyone is different and one man’s sperm may not be the same as the next. It should be noted that morphology is not the deciding factor when it comes to fertility and conception.