While answering a trick question posed by the pharisees, Jesus says marriage as we know it on Earth doesn't exist in Heaven. The book of Revelation gives us a picture of the greater spiritual reality that marriage points to (Revelation 19:6-7). However, that doesn't mean gender is going away. God creates Mankind male and female in Genesis chapter 1, and He calls it good. Jesus' own resurrection body is clearly male. At the Transfiguration, Elijah and Moses are called men and the original text uses male pronouns. Paul in 1 Corinthians 13:12 may indicate that our identity now carries over into how we are known in Heaven.
One verse that may be misapplied to this context is Galatians 3:28: There is neither Jew nor Gentile, neither slave nor free, nor is there male and female, for you are all one in Christ Jesus. The next verse tells us that ethnicity, economic, and gender differences have zero influence on our spiritual standing before God. However, ethnicity and gender differences can still have positive bearing on our daily life and they will in Heaven. John in Revelation 7:9 sees worshipers from nations, tribes, peoples, and languages, united but with recognizable distinctions. Revelation 22:2 says that the tree of life planted along the river in Heaven will have leaves that heal the nations. In Christ, our divisions our are healed, and our unique identities can be celebrated.