PregnancyThere are a certain number of things that need to happen to have a baby. Creating a human requires the right environment, the right factors, the right timing, and a lot of luck. The first stage occurs when an egg from a woman unites with a sperm from a man to form an embryo, the beginnings of a human being. This process is called design. After conception comes the process of fertilization, which is the process in which sperm must be present in the woman's reproductive system at the time the egg enters the fallopian tube. This can happen in several ways. If the woman has sex with a man during the week before ovulation, then he may deposit semen (a fluid containing sperm) into the woman's vagina. Some of the sperm can pass through the cervix (the opening to the uterus, located at the end of the vagina), enter the uterus, and travel up the fallopian tubes. There, one of them may encounter the egg as it travels down one of the tubes toward the uterus. Intercourse isn't the only way to get sperm into position. Another way is for a doctor to place sperm directly into the woman's uterus at the right time in her cycle, a technique called intrauterine insemination. These sperm can also travel up the fallopian tubes in search of the egg. Additionally, when sperm encounters the egg, they attempt to penetrate the outer layer of the egg. When successful, the outer surface of the egg forms a barrier to prevent other sperm from entering. The union of sperm and egg is called fertilization. The fertilized egg is the first cell of a new human being. It contains a complete set of genetic information necessary for a baby's development. Half of this genetic material comes from the mother, carried in the egg; the other half comes from the father, carried in the sperm. This means that the baby will have a combination of characteristics from both parents. The next step after fertilization is for the fertilized cell to float down the fallopian tube toward the uterus, where the cell divides in two. These two cells then divide to form four, and the division continues. About a week after fertilization, the growing cluster contains about 100 cells. We can now say that the woman carrying this embryo is pregnant and that the embryo is ready to go through the three trimesters of pregnancy. Duri...... middle of article ......ion/fine motor skills, learning difficulties and behavior problems. During pregnancy, many complications can occur. Some of these complications include birth defects, ectopic pregnancies, preeclampsia, and miscarriage. The most common birth defects are those associated with the brain and spine, heart and limbs. The other common defect involves the chromosomes of the fetal cells. (Ex. Down syndrome.) During an ectopic pregnancy, the fertilized egg attaches to a location other than inside the uterus. Most ectopic pregnancies occur in a fallopian tube. The narrow fallopian tubes are not designed to hold a growing embryo, so the fertilized egg in this type of pregnancy cannot develop normally. Preeclampsia is a condition in which the mother suddenly experiences a sudden increase in blood pressure after around the 7th month of pregnancy. This can be a life-threatening situation for the mother; usually, doctors ask her to give birth prematurely. Miscarriages are usually caused by abnormalities..