The germinal stage is the prenatal, developmental stage that begins at conception and lasts through the second week (that is still prenatal/before birth) of pregnancy. During this time, the fertilized egg (now called a zygote, and consists of a single cell) makes it way down the fallopian tube, and begins to have cell reproduction. Eventually, the single celled zygote becomes a multi celled ball that attaches itself to the wall of the uterus around the end of the second week, which constitutes the beginning of the embryonic stage.