Men and women are both made of atoms. It is objectively physically possible with sufficient effort to rearrange atoms* to turn one human into any other of equal or lesser mass regardless of gender**. The only question is: what's the smallest possible rearrangement which is sufficient to count?

If the surgical eversion of genitalia is sufficient, great, we got that.

If you require DNA, give it a few years.

* well, technically neutrons protons and electrons; I'm sure any two people will be slightly different in their counts of carbon atoms just from body fat percentages, or calcium from bone mass.

** regardless of if you mean the chromosome, the phenotype, or the social identity