After the fertilization process the combined cell makes its way through the remainder of the oviduct and it is planted in the uterus where, in nine months it develops into a full-term baby.
In the next nine months the child's body is in the making. Going back to the original cell, composed of the parent's united contribution, all cells which make up a person's body descend. Within days after the union of two cells these begin to form different cells, some are programmed to be muscle cells, brain cells, bones, skin and other parts of the body. As a product of this specialization of cells, the essential units are formed out of which tissues and organs will develop. When all the specialized cell combine properly, the various organs come into being, after the formations of organs different organ come together to form an organ system.
Four weeks after conception, the miniature structure which is going to be a human being, measures only one forth inch length which is almost a size of a rice grain. Astoundingly, however, the start of several important organ systems is already established. The four week old embryo has no arms and legs yet. The face seems to be very strange, and the shape of the embryo resembles a new moon. A bulge caused by a developing brain and another by a rudimentary heart are the most noticeable features of this stage. At this stage the digestive organs and the lungs are at the early stage. According to IMG health publication, at this stage the mother is experiencing vomiting, nausea, light-headedness, dizziness, exhaustion, and mood swings but not all women experience these symptoms. .
During the second month the embryo begins to increase in length and weight. It now measure 4 cm. long. The most conspicuous change is the development of the face with a forehead, blank eyes which just had developed eye lids, a mouth and a broad nose. Also the ears are starting to develop on the sides of the head.