Which pair of chromosomes produces a male off-springs?

Answer 1

It depends which species you are.

There is the XY system (which mammals use) where it is the presence of the Y chromosome that induces male development. The Y chromosome contains genes like Sry that initiate the male developmental program. Male mammals have an X and a Y chromosome, female mammals have two X chromosomes.

However, for other species, like birds, use the so-called ZW sex chromosome system where it is actually the absence of the W chromosome that permits male development - male birds have two Z chromosomes and female birds have a W and a Z chromosome.

And then there's the X0 system, which many insects use, where two copies of an X chromosome results in a female but a single copy of an X chromosome results in a male.

Answer 2

XX is female as the female only has X chromosomes. The father is the decider of the gender, he carries the XY chromosomes and a child needs XY to be male.