Poor Bobby cannot grasp that what is today fashionably called "gender" (optional, a matter of personal choice, can be altered at whim) is not the same as "sex" which is a matter of biological fact.
I wonder if he sincerely believes that two people of the same sex but different genders can make a baby together.
Sex is not binary. It can be ambiguous. I have presented numerous scientific evidence to support that point.
It is usual for a sex to be assigned at birth, by the parents or whoever is in attendance. But it may not, and sometimes does not fully equate to the actual genital or reproductive capability, if there is any.
It may not and sometimes does not equate to the gender perceived by the person concerned. They can change their gender, and the sex on their birth certificate.
So it's reasonable to describe sex as something assigned at birth and printed on the birth certificate, but that can be changed, just like gender can be changed.
So even though sex can be described as biological, it can be biologically ambiguous.
I'm not aware of any instances where sex determination is delayed until a full and detailed medical examination can be performed.
In other cultures, ambiguous sex is more acceptable, e.g. South Asian. It is much less acceptable in typical western countries.
And please stop being condescending with your silly questions and assumptions. It is not necessary, it is not worthy of you, and it suggests that you are not concerned with discussion, but more about insisting your opinion dominates.