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Very short answer No, not all males of all sexual species have Y chromosomes. You might want to have a look to the Wikipedia page on sex-determination systems. Long answer Diversity among the species that reproduce sexually Not all species that have sexual reproduction have sexes. Yeasts, for example, have mating types but no sex. Diversity among the ...


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No. There are many sex-determination systems. Mammals and fruitflies use the XX/XY sex-determination system — except for the platypus, which has 10 sex chromosomes. ZW sex-determination system is used by birds and some reptiles. It's similar but with the male having two of the same chromosome (ZZ) and the female being the heterogametic sex (ZW). There's ...


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The discovery of genetic sex determination, and determination of sex via male gametes (in XY species, female in ZW), occurred over some time in the late 1800's and early 1900's. Advances were made with methods to stain chromosomes and, in 1891, Henking noted that wasps produced sperm with a varying number of chromosomes. However, he was unable to gather ...


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There is at least one paper that claims this: A test for heritability of the sex ratio in human genealogical data is reported here, with the finding that there is significant heritability of the parental sex ratio by male, but not female offspring. --Trends in Population Sex Ratios May be Explained by Changes in the Frequencies of Polymorphic Alleles of ...


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Sex Determination System Birds have a ZW sex determination system meaning that males are the homogametic sex. Or yet, in other words, males have two Z chromosomes while females have one Z and one W chromosome. You might want to have a look at Do males of all sexual species have Y chromosomes? for a short review of the diversity of sex determination system. ...


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