Though the origin of the bra dates back to over 6000 years ago, it has evolved from being a garment that revealed the breast; to one that was supposed to make them smaller and more manlike; to one that made the breasts look symmetrical; to today's designer bras that have many different functions and designs.
All bras have a shoulder strap, cups, a center panel and a band with fasteners which are usually at the back but can be in the front. They are mostly made of cotton, or lace with underwire or plastic to give support and lift. Bras can be padded for comfort or to enhance the shape. Today there are even silicone gel pads that are more life like in both appearance and weight and can give even the most unendowed woman a feminine and alluring shape.
The full figured woman will mostly choose a full support bra for everyday wear and choose a demi-cup to wear with evening gowns or low cut tops. Shelf bras, which push up and display the breasts and peephole bras (where the nipples are shown through a cut-out circle) are worn mostly for sexual reasons. Most girls start out wearing a training bra, mainly to get used to wearing a bra: wearing a bra is considered rite of passage in our culture. Pregnant women will wear a maternity bra with fold down cups to allow for breast feeding a baby. A pad is usually inserted to prevent leakage of breast milk. Push-up bras are used to emphasize the cleavage, whereas minimizer bras are used to make the breasts smaller. Strapless bras are used when wearing evening dress, but most have detachable straps that can be added to the bra if needed. Bras designed to be worn with tee-shirts are seamless. Some clothes have a built in bra so a separate bra is not needed, thus eliminating two sets of straps. Women who are active in sports will wear a sport bra to support and prevent the breasts from bouncing and to reduce friction and damage to the delicate tissue. And lastly, the mastectomy bras has a prosthesis intended to allow her to look normal and wear her clothes with confidence.
So as you can see, the bra has many different functions in today's society and entire industries can be built around designing new and improved versions of an old stand-by.