![Twin Facts [1]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMmHeHylUSH9heGAcwq5mPhH3uG_ZUjiie2Mcu5Kt3gMLE__8msCoUdT6AsaQ_xcYnvNMRsNDWGNzfLUM1DGEaOehA7ItWNtA_Nf30cvqooWYo9vNpo-Oepsz1_0bHLDWpNf6dkUAZ_e3_OYX5i43qIjcO2fjQwwrCs9u_uqxRd57gEFlGPf8SVFEB/s16000/1396815268_05091e4cd5_o.jpg)
Vanishing twin syndrome:
You might have started out as a twin.
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| Photo by joel zobel |
Vanishing twin syndrome - when one of a set of twins or higher multiples disappears from the womb (it's actually absorbed by the woman's body) during pregnancy - occurs in 21-30 percent of multi-foetal gestation.
Now, given the high frequency of ultrasound testing, this incidence does not go unnoticed like it could have before the testing became so prevalent.
Conjoined twins
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| The Bunker brothers |
Conjoined twins are monozygotic twins who are joined at some region of their bodies.
The many different types of conjoined twins are classified by the area where the attachment is located.
Conjoined twins happen very rarely and the survival rate is quite low. While they happen about one time in every 40,000 births, they make up only one in every 200,000 live births. Research indicates that about 40 to 60 percent of conjoined twins are stillborn (deceased at birth).
And, another 35 percent remain alive for only one day after birth. Surviving twins are more often female than male. Even though more male pairs are conceived, the females lead the males 3:1 in making it to a live birth. There are probably less than 50 sets of non-separated conjoined twins living in the world today.
And, another 35 percent remain alive for only one day after birth. Surviving twins are more often female than male. Even though more male pairs are conceived, the females lead the males 3:1 in making it to a live birth. There are probably less than 50 sets of non-separated conjoined twins living in the world today.
Polar Body Twins
It is believed that these twins share 75 percent of their DNA; they share identical DNA from the egg and different DNA from the sperm.
Other Types of Twinning
Ever heard of twins who celebrate their birthdays months apart? What about twins who have different biological fathers? This seems impossible, but it turns out that both of these things happen. These incidents are rare, but real.
Some women can release more than one egg during ovulation and in some exceptional instances, these eggs are released at different times. Perhaps at 12 or even 20 days apart. Now, let's say both of these eggs are fertilized shortly after they are released. The woman conceives twins, but on two separate dates. Since the dates of conception differ, so will the dates of delivery. The twins could be born a couple of weeks or a month apart. This is known as superfetation.
