**Author details**

Desislava Dyulgerova-Nikolova1 \* and Tanya Milachich<sup>2</sup>

1 SAGBAL "Dr. Shterev", Sofia, Bulgaria

2 Institute of Biology and Immunology of Reproduction, Bulgarian Academy of Science, Sofia, Bulgaria

\*Address all correspondence to: dess\_ie@mail.bg

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
