Every month one egg sets out on a journey. If a sperm meets it in time, a new life begins; if not, the body resets and tries again.
- From puberty, usually one mature egg is released each month — this is ovulation ; the uterine lining thickens.
- During sexual intercourse, millions of sperm enter and swim up; a sperm may fuse with the egg in the oviduct to form a zygote (Fig. 11.20).
- The zygote divides repeatedly while travelling to the uterus and implants into its lining — marking the beginning of pregnancy.
In-vitro Fertilisation (IVF) is a technique in which an egg and a sperm are combined outside the female body, and the fertilised egg is implanted in the uterus. A baby born this way is commonly called a test tube baby . In 1978, Subhash Mukhopadhyay of Kolkata pioneered India’s first test tube baby, Kanupriya Agarwal (nicknamed Durga), through experimental IVF work.