Fertilization is the process where the egg (Female gamete) and sperm (Male gamete) fuse to form zygote .This process is happening in the ampullary region of the tube . Zygote on further development produces the embryo, the embryo implants or attaches inside the Uterus and develops into a fetus .
Normally in each menstrual cycle few small follicle (those which contains the immature egg) start development and only one among them will mature and release the mature egg (ovulation ) for fertilization with sperm. After fusion of the egg and sperm produces the zygote in the fallopian tube which develops into embryo. The early embryonic development occurs in the fallopian tube and the developed embryo after 4th or 5th day of fertilization reaches the uterine cavity and gets implanted on 6th or 7th day of fertilization.

Any block or abnormality in the above process is associated with infertility ,So knowledge about the conception is one of the most important thing when you seek for infertility treatment.