What does the Bible teach about same-sex practice?
The Bible defines marriage in Genesis 2:24 as a union between one man and one woman. Jesus Christ upholds this definition of marriage in Matthew 19:5, as does the Apostle Paul in Ephesians 5:31. Any and all sexual activity which takes place outside of this context is treated as sinful, what Jesus calls ‘sexual immorality’ in Mark 7:21.
Further to this, same-sex practice is specifically highlighted as sinful a number of times in Scripture. In God’s Law, for example, condemnations of same-sex practice are given in Leviticus 18:22 and 20:13. Further references are made in the New Testament. For example, in Romans 1:24-32, amid echoes to the Genesis creation account, both male and female same-sex practice are treated as sinful. Further references to the sinfulness of same-sex practice can be seen in 1 Corinthians 6:9 and 1 Timothy 1:10.
The Scriptures are, therefore, consistent in their prohibition of same-sex sexual activity, across different periods of salvation history and within different cultural settings. Although the Scriptures are clear on sexual ethics, they also tell us that the prospect of forgiveness and eternal life is held out for anyone who turns from sin and puts their faith in Christ (Mark 1:15), no matter how they may have fallen short of his good design for sex and marriage.
Resources for further study
Please note that any external resources below are intended to complement the main answer given above and may not entirely match TFT's position.