IntroductionLife begins when an egg and a sperm unite at conception. Over the last century technological advances in science have allowed humanity to take a closer look at our younger selves; specifically, the process of our development well before birth. During sexual intercourse, millions and millions of sperm are ejaculated into the vagina, few will enter the cervix, fewer will pass through the cervix, even fewer will find the fallopian tubes, only a small part will reach the egg and, finally, only one will fertilize the 'ovum (Parker). Once the fertilization period is over and the egg and sperm have successfully fused, the developing human begins its embryonic development, where it will spend the next eight weeks forming its major organs and other structures necessary to sustain life. As beautiful and exciting as this process can be, it can unfortunately lead to a number of complications once the baby is born. For example, trisomy 21 can occur due to nondisjunction, an error in cell division, resulting in an extra copy of chromosome 21, which will affect the child for the rest of his or her life (Ambreen). Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original EssayFertilization ProcessThe fertilization process begins with a male sperm and a female egg. Male sperm is made up of male sex cells, it is stored in the testicles as it needs to be kept cool to avoid higher temperatures resulting in infertility and its structure consists of a head, a body and a tail. The head includes a cap and nucleus, where genetic material, commonly known as DNA, is stored, the body contains mitochondria, where sperm energy comes from, and the tail provides swimming-like mobility as it contracts and relaxes (Rice ). On the other hand, the egg is the female sex cells. A female is born with all the eggs she will have in her life, the eggs are stored in the ovarian follicles located in the ovaries and around the age of 12-15 her eggs will begin to mature and be released once a month, developing the corpus luteum which thickens the wall of the uterus, preparing it for an egg (rice). The egg itself is a large cell, containing an outer cell membrane filled with proteins and a nucleus that stores the female's genetic material. Once the sperm and egg meet they fuse, this is known as fertilization; this can only occur during ovulation, a very short window of opportunity of about 2-3 days in which an egg is released and the sperm must reach the vagina quickly or it will die (Irving). After ovulation, the egg will be picked up by the fallopian tube from which it was released, and the sperm will have to swim through the cervix, past the uterus, to finally meet the egg in the fallopian tube (Parker). To complete the fertilization process, the sperm will have to enter the cell membrane of the egg and deposit its DNA, resulting in a now fertilized egg, otherwise known as a zygote (Rice), containing 23 pairs of chromosomes, equally distributed by the mother and from the father. The short period from fertilization until eight weeks of pregnancy is when the developing human being is considered an embryo. During the initial stages of embryonic development the process of cell division occurs, the zygote continues to divide to form the morula, a solid ball of cells, which will eventually become the blastocyst (Vitiella). About a week after fertilization implantation,).