The increased average maternal age and the excessive use of fertility treatments have led to the onset of multiple births. Over 90% of multiple births are twins. Twins may be identical (monozygotic twins) or fraternal (dizygotic twins).

A single fertilized egg (ovum) may produce two genetically identical offspring. This is in contrast to fraternal twins, in which two eggs (ova) are fertilized by two sperm to provide two genetically distinct offspring. It means they are not similar, like two siblings take birth at different times. 

The odds of a twin being a girl or a man are about the same. However, the frequency of having twins does not magically jump across generations, as most people believe. 

• Over 90% of multiple births are twins, which can be either identical or fraternal.
• Identical twins come from a single fertilized egg that splits into two embryos.
• The chance of having conjoined twins is about one in 100,000 births.
• Fertility treatments can increase the likelihood of having twins by stimulating ovulation.
• Conjoined twins share the same zygote but are physically connected in different ways.
• Women over 40 have a higher chance of having twins due to increased estrogen levels.
• Identical twins often develop a strong emotional bond and may even share a unique “twin language.”

There are different types of births. It’s not essential for a woman to give birth to a single baby at once. She can give birth to two, three, or more babies. It usually happens when more than one egg is fertilized or one egg gets fertilized multiple times with one or more sperm. 

Conjoined twins are identical twins connected to some parts of the body. They are monozygotic twins because they share the same zygote. Sometimes, they may also share the same internal organs. 

Conjoined twins might appear because of late twinning at least 12 days after egg fertilization.

Several variables contribute to the rise in the frequency of twin births. These include reproductive treatments, the average child-producing age, and genetics. It also involves certain environmental factors. Women somewhat older than the average age have a higher risk of having twins or other multiples. 

Some racial groups also have an increased probability of giving multiple births. On average, identical twins are born around once in 250 births worldwide. 

Some of these include:

It is a common observation that old-age women have higher chances of having twin births. The reason is that when a woman reaches the age of 40 or above; she produces more estrogen than a woman of twenty years. 

This increased estrogen production increases the chances of producing more than one egg at a time.

This is another common factor determining the chances of having twin babies. The higher the number of previous pregnancies a woman has, the more will be the chances of conceiving twins.

A woman with a previous family history of identical or fraternal twins will produce twins as well. Depending upon her family history, she might conceive with conjoined, identical, or fraternal twins. 

The incident of identical twins is also culture specific. For example, Black African women have higher chances of having twins than Asian women.

Many women undergo fertility treatments that involve the use of fertility drugs to produce eggs. This way, multiple eggs are released for ovulation, and the twins are formed.

Conjoined twins are also known as Siamese twins. It was named after the conjoined birth of popular Eng and Chang Bunker from Siam. There are few chances of a conjoined twin’s birth as one in 100,000 births. 

The probability of conjoined twins is higher in males rather than females. The respective ratio is 3:1. Meanwhile, conjoined twins have higher rates in certain countries like Africa and India. 

Because of the extreme physical intricacy involved, conjoined twins have a very low chance of survival. Most of them either aren’t born alive, and some may survive just for 24 hours. However, if no major organs are connected, a surgical separation of conjoined twins is possible. 

Conjoined twins may be classified in several ways, each of which has to do with the location of the body part they are connected to.

Some of their classifications may be cephalopagus, craniopagus, dicephalus, thoracopagus, and many more. Other two classifications of conjoined twins include; 

Parasitic Twins: It is where one twin is not completely formed and depends on the other for its survival. 

Fetus in Fetu: It is a rare occasion where one fetus is present in the other twin’s body.

Though separating conjoined twins is surgically possible, many people think it unethical. It is because there might be the chance of death or disability of one twin during the process. However, they can lead a happy and healthy life if they survive. 

They can even get married and make their family. There are many examples of sharing the happy marital life of conjoined twins, just like the famous Siamese children Chang and Eng Bunker gave birth to twenty-one children in thirty-one years of their marriage.

The average conception time for a single baby is 40 weeks, except for twins. The normal gestation period for identical or fraternal twins is 38 weeks. This is because when a woman is expecting twins, she develops the need for more nutrients. 

The child also becomes unable to receive adequate nutrients in utero. Because of this reason, the twins often get premature birth and have low birth weights. 

This premature birth increases the chances of birth anomalies like jaundice. 

However, many sets of identical twins seek and enjoy the benefits of building their own identities via their friendship selections. Interestingly, studies have shown that when twins have a strong bond, they also have greater friendships with their peers. 

Ultimately, twin babies should be nurtured as individuals and allowed to form their own identities and friendship networks, regardless of the number of friends they have already.