Reproduction (or procreation) of all beings is the biological process by which a new individual offspring is produced. It is a fundamental feature of all known life. [1] [2] [3]

The reproduction of human beings can be highly complicated. First, a male and a female individual have to find each other in order to come close to one another. During intercourse, the erect penis is introduced into the vagina. In the course of ejaculation, the man's seminal fluid containing male gametes (sperm) reaches the woman's reproductive organs. Then, sperm travels via cervix and uterus towards the fallopian tubes [INTERIOR VIEW] in order to find a female gamete (egg). If the time is right [FEMALE CYCLE], an egg is ready to be fertilized. The fertilized egg, called zygote, can implant in the endometrial lining of the uterus. This is how new life can develop. [3] [4]

However, a successful way to reproduction might be complex. On the one hand, it needs a suitable individual of the other sex. On the other hand, intercourse might be complicated due to physical or mental problems. Besides, the reproductive organs or gametes might be defective. [5]

Reproductive medicine aims at supporting people to procreate by using techniques like in vitro fertilization (IVF) or social freezing. This way, people who have problems with natural reproduction have the chance to comply with their wish to reproduction. There's still a lot of discussion on how far modern medicine is allowed to go and if each and every case is legitimate. [5] [6]

Further Links:
Warum sind Frauen kleiner als Männer?, Arte, 2013 (YouTube)