“…In this way, the Ca 2+ introduced from the extracellular medium is sufficient to restore the fertilization rates to normal, generally assumed as >70% oocytes showing two pronuclei (Tesarik & Sousa 1995, Tesarik et al 2002. Electrostimulation involves the application of a pulsed high-voltage electrical field, which modifies the plasma membrane lipid bilayer leading to the formation of pores, and therefore, allowing Ca 2+ entry from the extracellular medium (Versieren et al 2010 , resulting from Ca 2+ influx as well as from Ca 2+ release from the intracellular stores, particularly the ER, as described in starfish (Vasilev et al 2012); no data specific to mouse and human oocytes are currently available. …”