Not only do twins develop together inside of your uterus, but they also touch, kick, and sleep together right from the word go. (pregnancy-info.net)
We then can see if there is anything inside of the uterus that would prevent implantation and we can see if the tubes are open so that the egg and sperm can meet in the tube.» (kidsinthehouse.com)
The womb, called a «biobag,» is a plastic bag filled with fluid to mimic the conditions inside of a uterus. (scientificamerican.com)