This essay deals with the causes, probabilities, and dangers dealing with the occurrence of "multiple births." Extremely well-written, well-reasearched paper.
Multiple births are rare in humans with twins as being the most common form of this
event. Multiple births can arise in many different combinations of ways but the
probability of giving birth to more than one child remains fairly constant when compared
to the entire human race. The chances of multiple births can also vary from race and
genetic background. Scientist and researchers do not know what the exact cause of these
variations is but many of them feel that it is caused by hormone differences between
different racial groups and/or the difference in social class.
The prenatal and infant mortality is much higher in multiple pregnancies than in
pregnancies that only involves one child. The danger of premature birth also increased
with the higher number of offspring that are involved. In many multiple births, not all of
the children survived to childhood or were born dead. Through the advances in
technology, the survival rate of infants born in a multiple pregnancy has increased. The
first quintuplets, five babies born in a single pregnancy, to survive in medical history
were the Dionne quintuplets.
The use of drugs that treat female sterility, or fertility drugs, may increase the
chances of giving birth to multiple children. These drugs cause the ovaries to release an
egg once a month but in some cases they release more than one egg, sometimes releasing
several at a time, increasing the chances of a multiple birth. The drug clomiphene citrate
is one of the most widely taken fertility drug and has resulted in the birth of twins about
once in every twelve births, much greater than the chances of the birth of natural twins.
Twins are the most common form of a multiple pregnancy. About one in
eighty-seven births result in the birth of twins. Twins can be fraternal, also known as
dizygotic twins, or identical, also called monozygotic twins, with the birth of identical
twins being the rarest, occurring about four times in every thousand births, about
one-forth as often as the birth of fraternal twins. This ratio of the birth of twins to the
total number of births remains fairly constant but the birth of fraternal twins can alter
greatly. Fraternal twins are most common among black African followed by people of
European origin. Asian races originating from the orient are the least likely to give birth
to fraternal twins.
The birth of twins can occur in two different ways, the fertilization of a single egg
or the fertilization of two eggs. In the case of dizygotic twins, the woman's ovaries
release two eggs about the same time instead of one, with each being fertilized by the
male's sperm, fraternal twins begin to develop. The two zygotes develop differently, each
having a different genetic coding. They can be both boys,...