If you're positing that magic has a genetic basis, then you're also stating that there are 'organs' or at least 'chemicals' in the body that allow the manipulation of magical energy.
There's a significant importance here:
If there is a 'magic organ' created by having this genetic sequence, then having two copies of that sequence is going to result in a significant change from the single set version - the difference between the male and female body comes down entirely to that minor change in genetic material (although most of the physical changes are due to differences in horomones). Having two copies of the sequence describing how to produce 'organ X' is almost certainly going to result in a completely different organ - it may still perform the normal functions, but it may be either damaged or else super-effective, but either way there's going to be a significant difference. This is actually the less likely case, though.
The more likely case is that there is a 'magic hormone' or 'magic chemical' or both, which results in the production/maintenance of whatever physical/mental structures allow the use of magic. In this case, having two copies is going to significantly increase the amount of that chemical/hormone present in the body. Again, this will result in a significant change (although if it's more of an off/on function, this change may not be directly apparent).
As for men being significantly more powerful than women because of not having an X without that sequence, that's pretty much false. What you may have is a case where the X chromosome NORMALLY has a sequence that either suppresses or counteracts the effects of the Magic X, in which case a female with a Magic X and an Anti-magic X chromosome would be at a power disadvantage. But otherwise, there would be no distinguishable difference between male and female powers (except in the case of the Female with two magic Xs).
"Not this again!" Minerva said. "Albus, it was You-Know-Who, not you, who marked Harry as his equal. There is no possible way that the prophecy could be talking about you!" - Harry Potter and the Method of Rationality, Chapter 84
There's a significant importance here:
If there is a 'magic organ' created by having this genetic sequence, then having two copies of that sequence is going to result in a significant change from the single set version - the difference between the male and female body comes down entirely to that minor change in genetic material (although most of the physical changes are due to differences in horomones). Having two copies of the sequence describing how to produce 'organ X' is almost certainly going to result in a completely different organ - it may still perform the normal functions, but it may be either damaged or else super-effective, but either way there's going to be a significant difference. This is actually the less likely case, though.
The more likely case is that there is a 'magic hormone' or 'magic chemical' or both, which results in the production/maintenance of whatever physical/mental structures allow the use of magic. In this case, having two copies is going to significantly increase the amount of that chemical/hormone present in the body. Again, this will result in a significant change (although if it's more of an off/on function, this change may not be directly apparent).
As for men being significantly more powerful than women because of not having an X without that sequence, that's pretty much false. What you may have is a case where the X chromosome NORMALLY has a sequence that either suppresses or counteracts the effects of the Magic X, in which case a female with a Magic X and an Anti-magic X chromosome would be at a power disadvantage. But otherwise, there would be no distinguishable difference between male and female powers (except in the case of the Female with two magic Xs).
"Not this again!" Minerva said. "Albus, it was You-Know-Who, not you, who marked Harry as his equal. There is no possible way that the prophecy could be talking about you!" - Harry Potter and the Method of Rationality, Chapter 84