In humans, multi-fetal pregnancy occurs when a mother carries more than one fetus during the pregnancy. The most common multi-fetal pregnancy is twins, but mothers have given birth to up to eight children (octuplets) from ...

In 1934 a fourteen-day-old embryo was discovered during a postmortem examination and became famous for being the youngest known human embryo specimen at the time. The embryo was coined "the Yale Embryo," named after the ...

Rh incompatibility occurs when a pregnant woman whose blood type is Rh-negative is exposed to Rh-positive blood from her fetus, leading to the mother s development of Rh antibodies. These antibodies have the potential to ...

Stem cells are undifferentiated cells that are capable of dividing for long periods of time and can give rise to specialized cells under particular conditions. Embryonic stem cells are a particular type of stem cell derived ...

Quickening, the point at which a pregnant woman can first feel the movements of the growing embryo or fetus, has long been considered a pivotal moment in pregnancy. Over time, this experience has been used in a variety of ...

Many difficulties can arise with a pregnancy even after the sperm successfully fertilizes the oocyte. A major problem occurs if the fertilized egg tries to implant before reaching its normal implantation site, the uterus. ...

Meiosis, the process by which sexually-reproducing organisms generate gametes (sex cells), is an essential precondition for the normal formation of the embryo. As sexually reproducing, diploid, multicellular eukaryotes, ...