Why does the man secrete some liquid at the beginning of sexual intercourse

Patient's question:

Sex
Age
Detailed medical condition and consultation purpose: I had my first sexual intercourse with my girlfriend. Why did some liquid like pre-ejaculate come out when I first inserted it? What is this exactly?
Duration of the current illness and its persistence: Just the first time

Doctor's answer:

What you mentioned is prostatic fluid, which contains a certain amount of sperm. However, it needs to be clarified that fertilization between sperm and eggs requires certain conditions. If a woman has a significant amount of vaginal discharge, sperm may swim to the fallopian tube and combine with an egg. Additionally, the possibility of pregnancy during a woman's safe period is relatively low.
Advice: Based on the situation you described, the likelihood of pregnancy is low. If you are still concerned, you can use a self-testing kit 7 days after intercourse or take emergency contraception within 3 days after intercourse. It is recommended not to take emergency contraception more than once a month or more than three times a year.