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The human twin birth rate in the United States rose 76% from 1980 through 2009, from 9.4 to 16.7 twin sets (18.8 to 33.3 twins) per 1,000 births. [5] The Yoruba people have the highest rate of twinning in the world, at 45–50 twin sets (90–100 twins) per 1,000 live births, [6] [7] [8] possibly because of high consumption of a specific type of yam containing a natural phytoestrogen which may ...
In 1982, twins who were born with two different skin colors were discovered to be conceived as a result of heteropaternal superfecundation. [7] [5] In 1995, a young woman gave birth to diamniotic monochorionic twins, who were originally assumed to be monozygotic twins until a paternity suit led to a DNA test. This led to the discovery that the ...
Maternal immune cells are also found in the offspring yielding in maternal→fetal microchimerism, though this phenomenon is about half as frequent as the former. [ 11 ] Microchimerism had also been shown to exist after blood transfusions to a severely immunocompromised population of patients who suffered trauma .
This rare occurrence, when twins have the same mother but different fathers, is called superfecundation. This case is thought to be the first set of bi-paternal twins born in Vietnam, though there ...
Biparental inheritance is a type of biological inheritance where the progeny inherits a maternal and a paternal allele for one gene. It is one of the criteria for Mendelian inheritance. Sexual reproduction, where offspring result from the fusion of gametes from two parents, is the most common form of biparental inheritance.
Cross-siblings are individuals who share one or more half-siblings; if one person has at least one maternal half-sibling and at least one paternal half-sibling, the maternal and paternal half-siblings are cross-siblings to each other. [22] [dubious – discuss]
Twins are by far the most common form of multiple births in humans. The U.S. Centers for Disease Control and Prevention report more than 132,000 sets of twins out of 3.9 million births of all kinds each year, about 3.4%, or 1 in 30. [5] Compared to other multiple births, twin births account for 97% of them in the US. [6]
In this view, paternal care is an evolutionary achievement that compensates for the higher energy demands that reproduction typically involves for mothers. [60] [61] Other models suggest that basic life-history differences between males and females are adequate to explain the evolutionary origins of maternal, paternal, and bi-parental care.