Q&A: Pregnancy Upon Pregnancy Though rare among humans, it is possible for a second fertilization to occur when one pregnancy is already progressing. Share: Facebook Twitter Google+ Stumble Digg Email ThisBlogThis!Share to XShare to Facebook Related Posts:Trilobites: How Seals Took to the SeasSpace DISCOVERY: Dying star WIPED OUT entire system as 'heavy metal' planet debris foundCancer’s Trick for Dodging the Immune SystemHow Armstrong and Aldrin planted British flag on moon during Apollo 11 mission REVEALEDPlanet Nine SHOCK: Telescopes in Hawaii are hunting down mystery planet larger than EarthApocalypse Next? Astronomers Find a Chunk of Planet Around a Distant, Dead Star