It is a mystery why men are attracted to big breasts. Scientists have proposed different theories to explain this.

The mammary glands or breasts play a big role in human reproduction and sexual intimacy. In mammals, breasts are the primary way to provide nourishment to new born babies. Thus it is a key factor that determines whether an offspring can become healthy or not. However, attraction to bigger breasts is exclusive to humans.

Scientists say size promotes sexual bonding in humans. While men are attracted to bigger breasts, women are drawn to larger penises.

The attraction to breasts may have to do with the fact that humans are the only animal species that have sex facing each other. Other animal species normally have sex from behind. Since men see their partner's full front during sex, the female breast is thought to contribute to intimacy and attention.

Psychologists believe that the "hourglass" body shape in women - bigger breasts and bigger hips - transmits a signal to a man's brain that a woman is an ideal partner for child-rearing. This phenomenon happens unconsciously.

But the attraction to breasts is something learned therefore culture and environment plays a big role. In some cultures, larger breasts are attractive, while other prefer length than size. For some, shape and orientation is more important.

The researchers concluded that men are not hardwired to see bigger breasts as attractive, but are influenced to become so by the people around them as they grow up.

In the end, there is no definite answer to why men are attracted to breasts.