Why do women have two breasts?

Question

Humans have two ears so we can hear the direction the sound is coming from. (necessary for survival)
Humans also have two eyes so we can see in 3D. (also necessary for survival)
But what's the purpose of having two breasts instead of one, kinda like a male penis? What advantage does two breasts serve rather than symmetry?

please try to explain using the evolution theories, not creationism

Answer 1

IN development of a woman's breasts, during puberty, is triggered by sex hormones, chiefly estrogen. (This hormone has been demonstrated to cause the development of woman-like, enlarged breasts in men, a condition called gynecomastia, and is sometimes used deliberately for this effect in male-to-female hormone replacement therapy.)

In most cases, the breasts do fold down over the chest wall during development, ]. It is typical for a woman's breasts to be unequal in size particularly while the breasts are developing during puberty. Statistically it is slightly more common for the left breast to be the larger[10]. In some rare cases, the breasts may be significantly different in size, or one breast may fail to develop entirely.

A vast number of medical conditions are known to cause abnormal development of the breasts during puberty. Virginal breast hypertrophy is a condition which involves excessive growth of the breasts during puberty, and in some cases the continued growth beyond the usual pubescent age. Breast hypoplasia is a condition where one or both breasts fail to develop during puberty.
Other suggested functions
Zoologists point out that no female mammal other than the human has breasts of comparable size when not lactating and that humans are the only primate that have permanently swollen breasts. This suggests that the external form of the breasts is connected to factors other than lactation alone.

One theory is based around the fact that, unlike nearly all other primates, human females do not display clear, physical signs of ovulation.This could have plausibly resulted in human males evolving to respond to more subtle signs of ovulation. During ovulation, the increased estrogen present in the female body results in a slight swelling of the breasts, which then males could have evolved to find attractive. In response, there would be evolutionary pressures that would favor females with more swollen breasts who would, in a manner of speaking, appear to males to be the most likely to be ovulating.

Some zoologists (notably Desmond Morris) believe that the shape of female breasts evolved as a frontal counterpart to that of the buttocks, the reason being that whilst other primates mate in the typical doggy-style position, humans are more likely to successfully copulate mating face on. A secondary sexual characteristic on a woman's chest would have encouraged this in more primitive incarnations of the human race, and a face on encounter would have helped found a relationship between partners beyond merely a sexual one.


In Cameroon, some girls are subjected to breast ironing to stunt breast growth in order to make them less sexually attractive and thus become less likely to become a victim of rape.

Answer 2

The function of the breasts is to nurse the young. Thus, the number of breasts is in proportion to the number of babies typically born at once. That is why a female dog has six nipples; half a dozen puppies is a typical litter size. The fact that a human woman has two breasts indicates that the birth of twins would be typical. In actuality, single births are far more common, but twin births were perhaps more common in an ancestor species, or the duality is retained due to symmetry. In any event, it is partially for this reason that twin births are generally considered routine, while multiple births of larger sets of human babies are more difficult and exceptional.

Answer 3

Because a woman is capable of have one baby a year (except if she has twins or triplets, etc - which is really an exception more than the rule) and she will need the other breast to suckle the second baby - if she has a third baby soon after, the first one can already be given baby food. A second reason is because I have often noticed that a baby can finish off the milk in one breast and need "some more" - and so, it can be some sort of "reserved milk " if the baby needs more.

Answer 4

We had numerous breasts thousand years ago. You thought the fertility goddess statues are just symbolic, didn't you. Well, think again. In those times women gave birth to ten babies at once. But, as we all can guess, this isn't very healthy for the mother, because hungry babies can suck the life out of her. So, mother nature eliminated breasts one by one and now we are left with two. One is essential, the other is backup. That's how wise nature is. While you are at it, you may wonder why women have two ovaries, too.

Answer 5

OK, only 1 penis, but 2 testicles!
It's back up. What happens if one doesn't grow/form properly? What happens if you get a problem with the milk production or transmission?
Plus, from what I've heard, a baby can suck one breast 'dry' and still be hungry. There's a limit to milk production and storage. So you need two to make enough to feed a baby - plus for comfort!
What's more,. we can have twins... so you'd need two for two mouths
Any more reasons needed?
Question could be - why not 3?!?!?

Answer 6

The penis and scrotum form bilateral structures that fuse at the midline. Failure to fuse is not uncommon. Look up "hypospadias".

Why do (most) humans only have one pair of breasts? We only have one (usually) child at a time. For creatures that have litters, the ones we evolved from, bilateral arrangement was favorable.

We evolved from creatures with two side facing eyes for circumferential vision. Some things are evolutionary remnants.

Answer 7

It's actually really simple. Nature had to have a way to gurantee that humans will last. That means that nature had to create a way for humans to still reproduce without both breasts. If one breast was somehow not functional, or "cut" off, the other breast would still work. Just like men, if one "ball" was cut off, the other one will work fine. It's natures way of insuring humans reproduction.

Answer 8

1

Answer 9

1. Mammals (including the human being) generally have the next even number to the common number of offspring born at one time.
2. The number is even because mammals have a symmetrical body.

Answer 10

Speaking from my own experience, Men get into enough trouble with one penis.... and many many women have more than one kid. Besides, one big boob would look kinda funny. You'd look a bit like a...... cyclops from the neck down...