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Can you have twins of opposite gender?
In 99.9\% of cases boy/girl twins are non-identical. However, in some extremely rare cases resulting from a genetic mutation, identical twins from an egg and sperm which began as male (XY) can develop into a male / female pair. An XO baby is outwardly a girl, but her cells only have one copy of the X chromosome.
How common are male and female twins?
Fraternal twins, in which each of two eggs is fertilized by a different sperm cell, occur in about four of every 1000 births. About half of those result in male-female twin pairs.
Are twins more likely to be female?
This differs from fraternal twins, where two eggs (ova) are fertilised by two sperm and produce two genetically unique children, who are no more alike than individual siblings born at different times. Twins are more or less equally likely to be female or male.
At what age are you most likely to conceive twins?
Age. According to the Office on Women’s Health , women who are aged 30 years or older are more likely to conceive twins. The reason for this is that women of this age are more likely than younger women to release more than one egg during their reproductive cycle.
Can a male twin have twins?
A man with a family history of twins may carry the gene, but it won’t mean he can father a set of non-identical twins. The gene is only expressed through women who ovulate. If he has daughters, they may inherit the gene, and one day go on to have fraternal twins.
What are polar twins?
Half-identical twins are also called polar body twins. In theory, this results in twins who share half their genes in common (from the mother), but the other half of their genes are different because they come from two different sperm cells.
How to tell if twins are identical or fraternal?
Fraternal Twins. If you’ve got a boy and a girl that are twins,then congratulations!
Do identical twins need to be the same gender?
Identical (monozygotic) twins are always of the same gender because they form from a single zygote that contains either male (XY) or female (XX) sex chromosomes. Therefore, boy/girl twins are always fraternal or (dizygotic); they can only form from two separate eggs that are fertilized by two separate sperm.
Are identical twins always the same gender?
Identical twins are always the same sex and blood type. They almost always share the same placenta but may also have two separate placentas. Depending on when the egg splits usually determines if identical twins will share the same placenta, and/or chorions and amnions.
Can I get twins that are different genders?
These are the possible sex combinations: A set of boy/girl twins: Can only be fraternal (dizygotic), as boy/girl twins cannot be identical (monozygotic) Two boy twins: Can be either identical or fraternal (monozygotic or dizygotic) Two girl twins: Can be either identical or fraternal (monozygotic or dizygotic)