They do acknowledge intersexed people exist.
They believe they are the category of "eunuchs who were born that way" (Matthew 19:11). And should live single lives, the "difficult path" they have been given by God. Essentially they should be asexual and aromantic, and stay the gender that they are raised as and/or assigned as at birth.
They also believe that it is such a rare condition to be essentially irrelevant during debates.
As a Christian, I'll say: Hogwash all of it. But that's what they believe. You can find some of their writings online about it.
They are also the type that believes "God created them men and women" and that someone isn't in one or the other category is "less than" and a result of the curse. More hogwash that ignores the nature of God. But they use this argument against gays, saying that "without both parts, which God made different - both man and woman - a family is incomplete." It's vital to their theology and hate that no man can be womanly or vise-versa.