Oxford Dictionaries defines conception as the act of conceiving a child. More specifically, The Free Dictionary defines conception as the formation of a zygote after a sperm and female ovum unite; implantation must also occur.
WebMD explains that the idea of conception begins with a woman's ovulation. Each month in the ovaries, a group of eggs grows, but a woman's body only releases, on average, one per month. The egg follicle develops into a corpus luteum. Once an egg is released and is in the fallopian tube, the body puts forth hormones to thicken the uterine lining. When a man ejaculates into a woman, the sperm in the ejaculate move towards the egg. If a sperm makes it into the fallopian tube and buries itself into the egg, fertilization occurs. It is at this point that a baby's genes and gender are set. According to WebMD, sperm that carries a Y chromosomes results in a baby boy, while sperm that carries an X chromosome results in a baby girl. The fertilized egg stays in the fallopian tube for three or four days and as the egg moves from the tube to the uterus it begins dividing into many cells, which, in turn, make up the fetus and eventual baby, according to WebMD.