Biology is not necessarily limited to what identifiable chromosomes are present. For example, if a person with XY chromosomes has androgen insensitivity syndrome, that person has female characteristics that are visible to the observer, and therefore not imaginary.The problem with leftists is they actually think their beliefs make things real. Like the whole man thing. If someone with XX chromosomes sincerely believes they are a man then their chromosomes change to XY. If they say Christianity bis nonsense they actually believe that makes it nonsense. It's a very child like view of the world. They are an astronaut if they believe they are. Imagination is a wonderful thing.
Christianity is a belief/opinion that can be accepted or rejected and is based on faith.