Sperm determines sex

More about how the environment can affect sex ratios of children. The chances for a boy or a girl are a lot like the chances of getting heads. A female bluestreak cleaner wrasse can turn into a male when necessary. The Tech Interactive S. Market St.
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The Shettles Method of Sex Selection

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The Shettles Method of Sex Selection | The Embryo Project Encyclopedia

The XY sex-determination system is a sex-determination system used to classify many mammals , including humans , some insects Drosophila , some snakes, some fish guppies , and some plants Ginkgo tree. In this system, the sex of an individual is determined by a pair of sex chromosomes. Females typically have two of the same kind of sex chromosome XX , and are called the homogametic sex. Males typically have two different kinds of sex chromosomes XY , and are called the heterogametic sex. In humans, the presence of the Y chromosome is typically responsible for triggering male development; in the absence of the Y chromosome, the fetus will undergo female development. More specifically, it is the SRY gene located on the Y chromosome that is of importance to male differentiation.
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Is it a boy or a girl? The father’s family might provide a clue

A spermatozoon is a male germ cell capable of fertilizing an oocyte and carries genetic information for determining the sex of the offspring. It comprises autosomes and an X X spermatozoa or a Y chromosome Y spermatozoa. The origin and maturation of both X and Y spermatozoa are the same, however, certain differences may exist. Previous studies proposed a substantial difference between X and Y spermatozoa, however, recent studies suggest negligible or no differences between these spermatozoa with respect to ratio, shape and size, motility and swimming pattern, strength, electric charge, pH, stress response, and aneuploidy. Moreover, recent proteomic and genomic studies have identified a set of proteins and genes that are differentially expressed between X and Y spermatozoa.
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A sex chromosome is a type of chromosome that participates in sex determination. Humans and most other mammals have two sex chromosomes, the X and the Y. Females have two X chromosomes in their cells, while males have both X and a Y chromosomes in their cells. Egg cells all contain an X chromosome, while sperm cells contain an X or Y chromosome. This arrangement means that it is the male that determines the sex of the offspring when fertilization occurs.
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