Race – African-American women are more likely to have twins than any other race. Asian and Native Americans have the lowest twinning rates. Caucasian women, especially those over age 35, have the highest rate of higher-order multiple births (triplets or more).
African-American women are more likely to have twins than any other race. Asian Americans and Native Americans have the lowest twinning rates. White women, especially those older than 35, have the highest rate of higher-order multiple births (triplets or more).
Africa has a high rate of twins born naturally from two separate eggs, and according to the study 80% of twins are now born either in Africa or Asia.
Older women generally have a higher chance of conceiving twins. A 35 year old woman is about 4 times more likely to have fraternal twins than a 15 year old! That is because they are experiencing some hormonal changes as they near menopause. This could encourage their body to release more than one egg during ovulation.
The age of the mother and the order of birth being equal, the dizygotic twinning rate is twice as high in Sub Saharan Africa, than in Europe, and four to five times higher than in China or Japan. These variations are partly linked to hormonal differences of genetic ori- gin (2);
Asian and Native Americans have the lowest twinning rates. Caucasian women, especially those over age 35, have the highest rate of higher-order multiple births (triplets or more).
The Science of Fraternal Twins. Mixed-gender twins are the most common type of fraternals, some 50 percent are boy-girl.
This is why fraternal twins run in families. However, only women ovulate. So, the mother's genes control this and the fathers don't. This is why having a background of twins in the family matters only if it is on the mother's side.
The quick answer to this question is that, in a twin pregnancy, it is the mother's genes that determine twins. First up, giving birth to identical twins is not genetic, but conceiving fraternal twins is. The mother may have the genetic trait of releasing two eggs in one menstrual cycle.
Women who have overweight or obesity also have a higher chance of conceiving twins naturally. Specifically, the chances are highest if your body mass index (BMI) is above 30, according to a 2005 study that looked at data from more than 51,000 births in the United States.
The other reason for the twincrease in the developed world is the proliferation of fertility treatments like in vitro fertilization and ovarian stimulation, which increase a woman's chance of a multiple pregnancy.
Birth rates for MZ twins are consistent among all races (about 4 per 1000); but the incidence of DZ twinning varies among races (8 per 1000, among Caucasians, 16 per 1000 among people of African descent, and 4 per 1000 among Asians).
A big reason for all those twins is an increase in medically assisted reproduction, including in vitro fertilization, ovarian stimulation and artificial insemination. Another reason is that women in many countries are having babies at older ages.
Identical twins have 100% of their DNA the same while fraternal twins share only 50%. But what about semi-identical twins? Well, they have 75% of their DNA the same.
While men can carry the gene and pass it on to their daughters, a family history of twins doesn't make them any more likely to have twins themselves. 3 But, if a father passes on the "twin gene" to his daughter, then she may have a higher chance than normal of having fraternal twins.
Everyone has the same chance of having identical twins: about 1 in 250. Identical twins do not run in families. But there are some factors that make having non-identical twins more likely: non-identical twins are more common in some ethnic groups, with the highest rate among Nigerians and the lowest among Japanese.
Many people believe twins skip a generation, but that's just a myth. The idea that twins skip generations likely comes from the fact that the genetic factors contributing to twins only come from the gestational parent's side.
It's equally unsurprising that a Danish study found that twins are less likely to get married than non-twins. As twins have a partner from birth, the study suggests that they may not have the same desire for marriage as singletons.
While 40 weeks is the full gestation period of the average pregnancy, most twin pregnancies are delivered at approximately 36 weeks (range 32-38 weeks depending on the type of twin pregnancy).
The fertility rate in the United States in 2020 was 56.0 per 1,000 women ages 15-44. Of all live births in the United States during 2018-2020 (average), 23.7% were Hispanic, 52.1% were white, 15.2% were black, 0.8% were American Indian/Alaska Native and 6.8% were Asian/Pacific Islander.
In fact, one British study tested ESP potential among identical twins and found that they were correct about 25% of the time, the same as any other siblings. There is one particular power though which twins possess, longevity. Fraternal twins live longer than singletons and identical twins longer still.
For women born 1870-1899, moms of twins averaged reproductive spans of 14 years 11 months versus 14 years for singleton moms. Both results were statistically significant. Moms of twins also were older at the time of their last birth.
Twins and other multiple-birth individuals can suffer from much deeper and troubling loneliness than single-born individuals. Separation anxiety, which often begins at birth, is the underlying cause of loneliness for twins.
In 2021, according to the Australian Bureau of Statistics (latest report as of October 2021) there were 4,248 multiple births representing 1.5% of all births (309,996) in Australia. This comprised 4,185 pairs of twins and 63 sets of triplets and higher order multiples.
The percent of people who are twins differs by race and ethnicity. In the U.S., twins are most common in African-Americans (36.8 per 1000) and least common in Hispanic/Latino Americans (21.8 per 1000).