Researchers at the University at Buffalo found a link between specific sperm abnormalities and low pregnancy rates. They discovered that samples with premature chromosomal decondensation or acrosome reactions had only a slim chance of leading to a pregnancy.
Researchers at UCSF have identified a critical gene involved in yeast spore development that may also play a role in human sperm development. The study found that a gene called NDT80 stimulates the synthesis of proteins necessary for DNA division, and its malfunction can cause permanent arrest in sperm development.
Research reveals estrogen regulates fluid reabsorption in efferent ductules, essential for sperm maturation and normal fertility. The study found high concentrations of estrogen receptors in the male reproductive tract.
A reanalysis of international data reveals a significant decline in sperm density across the United States and Europe, with the rate of decrease varying by region. The study found an average annual decrease of 1.5 million sperm per milliliter in the US and 3.1% per year in Europe.
Researchers found that mating is more harmful to females than egg laying, with costs imposed by males leading to female survival and reproductive value depression. In contrast, egg production has a minimal impact on female fitness under certain conditions.
A study by the University of Pennsylvania School of Medicine found that postmortem sperm procurement requests are increasing, with over half made between 1994 and 1995. Most requests were from wives seeking to create children for their deceased husbands.