What Are Twins?

Ayazhan Zhaksybayeva
Jan 10
3 min read

How are identical twins formed ?

Identical twins form when an egg has been fertilized by one sperm, and the zygote ( single celled organisms formed by the fertilization of an egg and a sperm) splits into two. This separation happens at the early stages of pregnancy and when it divides early in pregnancy this can indicate that both babies will have the same genetic information.

Identical twins can also occur when one a woman has undergone fertility assistance and has had one fertilised egg returned to her uterus. If this egg then splits into two, an identical twin pregnancy can result.

Why are identical twins not really identical ?

A lot of identical twins have the same DNA cells, but their cells can make different proteins depending on how the DNA is regulated and packaged. Which may lead to having differences. When the zygote forms during pregnancy a lot of cells don't change later during the period of life. But environmental factors such as (nutrition, stress, hormones, illness, and lifestyle ) may change the gene expression of the twins. If two twins have different lifestyles this will change the ageing difference, height, weight and even facial features. But these environmental factors don't change the DNA code.

What are mirror twins ?

Mirror twins, or mirror image twins, is used to describe a characteristic of some twins whose features appear asymmetrically, that is, on opposite sides. When these twins are facing each other, it is as if they are looking in a mirror. Mirror twins fall into the identical twins category, but have opposite characteristics.

Physical traits : Birthmark, moles, dimples, eye shape, ear shape and hair whorls. Having these features but opposite sides of their faces, having hair whorls may be clockwise but anticlockwise for the other twin.

Some twins use different hands, eg : One twin uses their right hand the other twin uses their left hand.

Causes of Mirror Twinning:

Because mirror twins may occur with monozygotic twinning, it's been theorized (and disputed) that mirror image twinning occurs when the egg splits later on during development. This could happen more than a week after conception, but not late enough so that conjoined twins form.

How are fraternal twins formed ?

Fraternal twins are just like any other brothers and sisters in a family and share the same biological parents. The only difference is that they happen to have been formed in the same month and shared their mother’s uterus during the same pregnancy. Other names for fraternal twins are non-identical twins as they form from two completely separate eggs and sperm. This is different to identical (one egg) twins who form as a result of one fertilised egg splitting into two identical little people.

What are conjoined twins ?

Conjoined twins are two babies who are born physically connected to each other. Conjoined twins develop when an early embryo only partially separates to form two individuals. Although two babies develop from this embryo, they remain physically connected most often at the chest, abdomen or pelvis. Conjoined twins may also share one or more internal body organs.

Is Twin telepathy real ?

Some people might say that it is true, some people don't believe it but if you ask a twin they might say it is true. This is because they have this deep connection that is not physically but it is mentally. Their DNA doesn't play a role in these behaviors.

They can sense each other's feelings, thoughts, and even physical sensations. This theory is not scientifically approved, however many twins do say that they can feel it.