News tagged with sex

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HIV risks high in Mexico City's male sex trade

A new study documents the stark health dangers of the male sex trade in the streets, hotels, and discotheques of Mexico City. Lead author and health economist Omar Galárraga's point in making the grim assessment ...

Nov 14, 2014
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Vitamin D levels examined for long-term health effects

A West Australian study has recorded the vitamin D levels of local children, along with the genes involved in its production, setting the foundation for future research into vitamin D effects on a person's ...

Nov 05, 2014
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Australians having less sex than a decade ago

A major study into the sexual health and well-being of Australians – Sex in Australia 2 – reveals that sex in relationships occurs 1.4 times a week, down from the 1.8 times a week reported by more than ...

Nov 07, 2014
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Sex

In biology, sex is a process of combining and mixing genetic traits, often resulting in the specialization of organisms into male and female types (or sexes). Sexual reproduction involves combining specialized cells (gametes) to form offspring that inherit traits from both parents. Gametes can be identical in form and function (known as isogametes), but in many cases an asymmetry has evolved such that two sex-specific types of gametes (heterogametes) exist: male gametes are small, motile, and optimized to transport their genetic information over a distance, while female gametes are large, non-motile and contain the nutrients necessary for the early development of the young organism.

An organism's sex is defined by the gametes it produces: males produce male gametes (spermatozoa, or sperm) while females produce female gametes (ova, or egg cells); individual organisms which produce both male and female gametes are termed hermaphroditic. Frequently, physical differences are associated with the different sexes of an organism; these sexual dimorphisms can reflect the different reproductive pressures the sexes experience.

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