For a human male offspring, the correct answer is that the offspring must have one X chromosome and one Y chromosome. Other species don’t necessarily follow this model, but there is always a way to tell which chromosomes code for male and which code for female. This answer will focus more on human biology than general biology, as that is the best way to answer the question.
Though all humans have at least one X chromosome, this creates an interesting issue. It means that all humans start as female, but as time goes by in the womb, the Y chromosome activates and turns the fetus male. This change comes around six weeks, and gives the baby the traits that most think of when it comes to a male baby.
