Scientists from the University of Toledo were completely surprised to discover a previously unknown structure in the human sperm, since sperm cells are well-studied.

The new study, which was published online June 7 in the journal Nature Communications also found that the new structure could contribute to infertility, miscarriages and birth defects.

However, the positive thing here is that once the researchers understand this structure better, it may assist them develop new therapies for male infertility and learn more about early human embryonic development.

The researchers found that the newly identified structure is a centriole, which they referred to as 'atypical' centriole, which is a barrel-shaped structure made of short microtubules. They knew that sperm cells contain one centriole, but the new discovery brings the total to two centrioles per sperm.

The New centriole is said to have a number of funny properties. Though they have the same function, both centrioles look very different.

Tomer Avidor-Reiss, from Toledo's Department of Biological Sciences, in a press release said "Abnormalities in the formation and function of the atypical centriole may be the root of infertility of unknown cause in couples who have no treatment options available to them."

"It also may have a role in early pregnancy loss and embryon development defects."

Previously, researchers thought that sperm carried just one centriole, which then duplicated itself if the sperm met an egg. That's because the egg does not have a centriole, while a zygote, or a fertilized egg, needs two centrioles to start the development of a fetus, the researchers said.

These centrioles play a pivotal role. They are needed for building the cell's cytoskeleton (the structure that maintains cell shape) and completing accurate cell division, the researchers noted.

"Since the mother's egg does not provide centrioles and the father's sperm possesses only one recognizable centriole, we wanted to know where the second centriole in zygotes comes from," Avidor-Reiss said.

"We found the previously elusive centriole using cutting-edge techniques and microscopes. It was overlooked in the past, because it's completely different from the known centriole in terms of structure and protein composition."