Fertilization in humans, also known as conception, is the process by which a sperm cell from a male and an egg (ovum) from a female combine to form a zygote, marking the beginning of a new individual’s development. The process of human fertilization involves several key steps:

1. Ovulation: In females, ovulation is the release of a mature egg (secondary oocyte) from one of the ovaries. This usually occurs around the middle of the menstrual cycle and is triggered by hormonal changes, primarily the surge of luteinizing hormone (LH).
2. Egg Maturation: The released secondary oocyte is arrested in metaphase II of meiosis, and it will only complete meiosis if it is fertilized by a sperm.
3. Sperm Transport: Sperm cells are ejaculated from the male’s reproductive system during ejaculation. They enter the female’s reproductive system through the vagina and travel through the cervix and uterus, ultimately reaching the fallopian tube, where fertilization typically occurs.
4. Meeting of Sperm and Egg: The sperm cell must find its way to the egg within the fallopian tube. This journey is facilitated by the sperm’s ability to swim and navigate toward the egg. It is a highly competitive process, as many sperm cells may be attempting to reach the same egg.
5. Fusion of Genetic Material: When a sperm successfully penetrates the egg, it triggers the completion of meiosis in the egg. This results in the formation of a diploid zygote, containing a combination of genetic material from both parents. The genetic material from the sperm and the egg combines to create a unique set of chromosomes in the zygote.
6. Formation of the Zygote: The fertilized egg, now called a zygote, undergoes its first cell division shortly after fertilization. This division marks the beginning of embryonic development. The zygote continues to divide as it travels through the fallopian tube and eventually reaches the uterus.
7. Implantation: Once the developing embryo reaches the uterus, it undergoes further cell divisions and differentiates into a blastocyst. The blastocyst implants itself into the uterine lining, where it will receive nourishment and continue to develop.

Fertilization is a highly regulated and complex process, and it is the first step in the development of a new human being. It involves numerous biological mechanisms and a specific sequence of events that must occur in the female and male reproductive systems to create a zygote with the genetic material needed for the development of a unique individual.