Level 1: The physiological basis of female intercourse. During menstruation, a female\’s ovary will release an egg. If she has sexual intercourse with a male at this time, the sperm will enter the female body and combine with the egg to form a fertilized egg. This fertilized egg travels through the fallopian tube and eventually implants on the inner wall, forming an embryo. This is what pregnancy is like. Level 2: Things to note when having sex. You need to pay attention to the following points when having sex: 1. Maintain safety measures: Using condoms can effectively avoid unwanted pregnancy and sexually transmitted diseases.