The first study to investigate the morphology of sperm classified spermatozoa with abnormal morphology as abnormal. The results of this research were published in a prestigious biochemical journal. The morphological features of normal acrosome-shaped sexed ovules, tails, and heads were described. Researchers later added secondary morphological features to the list.
Sperm with abnormal morphology show different patterns, such as giant head, pinheads, and uniformly rounded heads. They are characterized by an absence of acrosomes. In some cases, the acrosomes may not be present, so the sperm is considered acephalic or decapitated sperm syndrome. In such cases, a small sperm may appear like a pinhead, but upon close examination, it will show that there is no head. In other abnormal morphology of acrosomes, the acrosomes are completely absent. In this case, the acrosome will be missing.
Other morphological defects of sperm include oval and banana-shaped heads, amorphous and tapering sperm, and amorphous and borderline forms. As of 2013, there are six major categories of amorphous sperm. During the last century, these categories have been revised. In the same way, the amorphous sperm were classified into two classes: large and small sperm, oval-shaped oocytes, and amorphous oocytes.
Infertility is a common problem for couples and individuals in general. However, the morphology of sperm cells is not completely determined by environmental factors, which makes them an important part of the puzzle in the case of globozoospermia. Despite its common appearance, the underlying molecular mechanisms of globozoospermia remain largely a mystery. There are several important steps needed to improve the percent of normal spermatozoa in the human population.
The morphological features of sperm are outlined in the 9th report on spermatozoa in humans. This report also states that the head and tail of a spermatozoa must be a regular oval shape and have a flat, round or rounded body. The acrosome and the tail must also be axially attached. If there are abnormal morphologies, the acrosome should be reshaped.
Abnormal morphology of sperm is categorized as teratozoospermia. This disorder is caused by a lack of the CFAP69 gene. CFAP69 is a regulatory gene that controls the olfactory transduction kinetics in the human olfactory system. Mutations in this gene cause severe defects in the axoneme, and MS of sperm.
Molecular morphology is a major factor in determining a person’s fertility. Abnormal morphology can be caused by genetic abnormalities and stress. This condition is reversible if the cause of the stress is removed. A single adversity attack may cause a temporary reduction in sperm morphology, but repeated assaults may result in permanent lower sperm values.