Cheryl Schaltz gave me a reason why Christ had to be male. And also, why women came from man, and was not created separately.
Sin entered the world through Adam:
Rom 5:12-14 Therefore, just as sin entered the world through one man, and death through sin, and in this way death came to all people, because all sinned—
To be sure, sin was in the world before the law was given, but sin is not charged against anyone’s account where there is no law. Nevertheless, death reigned from the time of Adam to the time of Moses, even over those who did not sin by breaking a command, as did Adam, who is a pattern of the one to come.
(How could it be that sin entered through Adam, as Eve ate first?
1 Tim 2:14: And Adam was not the one deceived; it was the woman who was deceived and became a sinner.
Eve was deceived and thus ate, Adam ate on purpose, is her answer.)
Rom 5:19 For just as through the disobedience of the one man the many were made sinners, so also through the obedience of the one man the many will be made righteous.
A female Jesus would not have been a second Adam, say Cheryl Schatz, thus the Messiah had to be male. If Eve was made separately and not from Adam, and Jesus came from only a human mother, Jesus would not have shared genes with Adam, and thus not be the second Adam either.
(Her reason why Jesus had a female human parent and not a male one – sin is allegedly carried to both men and women through the male genes – is one you can test against scripture for yourself. But that is a separate issue from “did Jesus have to be male to be the second Adam?”)