In heaven, there is no gender because gender is only for reproduction. There is no reproduction in heaven. All the inhabitants of that realm, with the exception of God himself, are created not born.
When God created humans, he created an arrangement whereby the male was the 'President' or head of his company (family) and his wife was the Vice President, or second in command. Children would naturally be subject to their parents, following the pattern that Paul mentioned in 1 Corinthians 11:13...
"But I want you to know that the head of every man is the Christ; in turn, the head of a woman is the man; in turn, the head of the Christ is God."
So in God's arrangement, the male is the head of his household, not in a dictatorial way, but in a way that shows love and consideration for all members of the family....as Christ loved the congregation. (Ephesians 5:25) The man is subject to Christ and Christ is subject to God (ruling out any notion of a triune equality)
In God's family there is headship pertaining to their individual roles....and since the woman is subject to the man, portraying a Jesus as female would have been out of character with this arrangement because God portrays himself as male and refers to his son as such, even though they themselves are genderless in heaven.
Add to that the fact that Adam was a male and that it was his sin that plunged us into this situation in the first place.....a male life was given for an equivalent male life.