'Sadly, some influential voices within the modern church have been tempted to define Christian "love" as neutral soil into which we can plant whatever we choose. Giving his support to same-sex marriage, for instance, former pastor Rob Bell draws on Genesis 2 to explain that we need more love, more monogamy, more fidelity, and so on. When asked if he is "for same-sex marriage," he replied, "I am for marriage." Yet Genesis 2 is a strange text to use for such an assertion, forming as it does the cornerstone of Christian sexual anthropology. It shows that intimacy within heterosexual marriage is purposeful or teleological (it can bear new life), normative (it expresses God's intended design for sexual relationships), and comprehensive (the complementary natures and bodies of men and women in marriage are a reflection of God.).
Bell's theological innovation replants Eden with a new moral ecology. Yet Christian love, as brought to life in scripture, is a flourishing garden with defined walls and keen discernment regarding what we cultivate and which fruit we taste. Even more so, following our retreat from Eden, there is a presumption that what we should cultivate is not what naturally grows within us. Indeed, our deepest desires are likely to lead us astray, and it took nothing less that God-in-the-flesh to reverse that destructive dynamic. It is strange, then, that parts of the church have been so eager in recent years to bless almost any form of sexual expression provided it is given and received with genuine feeling and continuity. This development is a reflection of the modern authentic self rather than the genuine Christian self. It demonstrates why Christian desire must be trained within the boundaries of Christian truth.'
Jonathan Grant, Divine Sex, p.177.