Why did humans come up with the idea of covering up genitals and breasts (for women) in the first place?

 

There is not a singular reason for a culture to have decided to cover the genitals, the breasts, or both.

Some basic research shows that many cultures that survived to modern day did not require coverings to function adequately in day to day life.

Below you can see members of tribes from South Sudan. Men did not cover their genitalia at all in day to day life, and neither did women. They had complex adornments in the way of jewelry, belts, and amulets that would signal class and wealth:

Dinka woman. The beaded belt signals wealth.

Dinka man

Nuba woman:

Nuba man

For some cultures, covering the genitals became a way of signaling that the individual is not sexually available. In some, it did not involve an actual covering, but some type of adornment or etiquette.

In most cases, the reason was that the individual was already in a committed relationship or married.

In other cases, the reason is that the individual is maturing sexually. This would be a common situation for cultures in which marriage is decided after some time has passed beyond maturation.

Below, you can see women of the Xingu tribe in the Brazilian Amazon. Women remove genital hair. They wear a fiber belt with a wood adornment in the middle. A thin strip of fiber is passed front to back, in between the external labia and the buttocks, symbolically sealing the openings.

Below, you can see individuals of the Zo’e tribe, also from the Amazon. Women leave their genital hair natural and do not cover their genitalia. Men tie a small strip of fiber around their prepuce, sealing their glans inside. This is the “proper” way to show yourself for men and they only removed it for urination or sex.

Below, you can see individuals of the Huaorani tribe. Women did not cover their genitalia. Men tuck their prepuce under a fiber belt. This, as in the Zo’e, is the usual “proper” way of keeping the penis around others.

The majority of cultures that saw a reason to differentiate “available” or “maturing” or “proper” by covering their genitalia, did so with a fabric or leather cover.

Below are members of the Khoisan people of South Africa. They men wore a leather loincloth covering the genitals, women a leather skirt

Below are members of the Embera tribe of Panama . Men wore a cotton loincloth, women a skirt.

Below are members of the Bora tribe. Both men and women wore a fiber skirt.

Throughout history, many, many cultures have not considered the breast a sexual organ, and despite complex conventions about covering the genitalia, left the breast uncovered, or would cover it some time for reasons of temperature and sun exposure management, but would not be concerned about it being displayed.

Below are images from ancient Kerala, in India. Men wore a loincloth, and women wore a skirt. A chest covering would be worn variably to protect from cold or sun, but the breast did not need to be hidden.

Below are images from ancient Ama divers of Japan. These women divers dove nearly nude for shellfish, wearing only a thong genital covering made of rope and cloth.

Ama on boat readying to dive

Ama ready to dive

Ama diver searching the sea floor for shellfish

Finally, many cultures, the breast became associated with reproduction and sexuality, and for that reason it became customary to cover it at all times. We are all familiar with that.

Interestingly, the covering the genitalia as a means of protection from the elements is not very likely to be a major reason. Many cultures in different environments never saw a reason to cover it for protection, so this is not likely a primary reason.