I get lots of good questions that come my way. This one was a little different in that I couldn't turn to any books on my shelf for a ready answer - trust me, I tried. I scoured my theological text books, books on sexuality, and books on being created in the image of God. There were of little or no help whatsoever. So, I'm posting (with permission) the question and my thoughts. Feel free to pipe in!
The question: [Some friends and me] were talking about how Jesus had the capacity for sexual feelings and was, therefore, a sexual being. Jesus had sexuality and all humans are sexual individuals; however, I was wondering if Jesus had sexuality before he became a flesh and blood human or if the sexuality was a result of his being a creature on earth. And in turn, I'm wondering if our souls have any sort of capacity for sexual feeling, or if our sexuality is a result of our creatureliness. If Jesus had the capacity for sexual feelings before he came to earth then that would mean the sexuality exists in perfection in the Trinity...which seems strange to me - that would indicate that sexuality exists for some sort of purpose in the Trinity.
My thoughts: First, I think it's important to be precise when we discuss sexuality. You said 'all human beings are sexual creatures', and in a sense that is true. Everyone is either male or female [with the rare exception of hermaphrodites. still, in those case they either are XY or XX, I think, so technically still male of female. I would attribute this condition of the fall and the radical effects of sin on humanity]. I don't know if we can say 'all humans have sexual attractions'. I think there are plenty who do not. Certainly there are time of life when not all humans do - young children, older adults (before Viagra). That doesn't mean children or the elderly are less human, or even less male or less female.
Second, I think there is someway in which male and female as distinct genders reflects the image of God more adequately that just male or just female. I'm not willing to say, with Barth for example, that the image of God = male/female, though I do think the distinction is important to understanding the image of God. That being said, I would affirm that God the Father, God the Son and God the Holy Spirit all equally share in the essence of deity that is reflected in the male/female distinction. In other words, one isn't more masculine and another more feminine. They equally share an essence and attributes that required maleness and femaleness to reflect. Though the overwhelming majority of images of God in the Bible are male, there are some that are female (like a 'mother hen', etc.).
Third, considering Jesus, I believe he shares the same essence as the Father and the Spirit before his incarnation (as he does during and after as well). This essence was not imaged in just maleness or just femaleness, but in both together. While it's certainly true that the pre-incarnate Son isn't strictly male in a biological sense (no Y chromosome), yet I believe it is very significant that the preponderance of imagery is male. I'm not at all suggesting we should adopt gender neutral language ('he/she', Mother/Father) when it comes to God or the Son. Still less am I suggesting we refer to God as 'it'.
I do not believe he was a sexual being (in the sense of sexual attraction or even sexual 'equipment') before the incarnation. I think that comes with the 'in the flesh' dynamic of the incarnation. I believe sexual attraction, intimacy and pleasure are pale reflections of the intimacy and mutual pleasure that exist between the persons of the Trinity from eternity. They are creaturely/physical manifestations of and paths to oneness and love.
Lastly, the issue of our souls having the capacity for sexual feeling is, in my opinion, off mark. We need to be careful of the ever present danger/heresy of gnosticism which speaks of body/physicality as bad and souls/spirituality as good. Gnostics portray salvation as escape from physicality and that language comes into evangelical vocabulary in phrases like 'saving souls'. As I understand Scripture, there is only a short period of time when our souls will exist apart from our bodies. Our souls will be separated from our bodies during the 'intermediate state' - after our deaths but before the return of Christ and the resurrection of the dead. Once Christ returns and the dead are raised, we will exist eternally in resurrected bodies, our souls having been reunited with our their physical counterparts. There's little evidence here, but I assume we will still exist as either male or female - though a strong argument could convince me otherwise. So in that way we'll exist as sexual creatures even in eternity. Yet I don't think we'll have sexual attractions or impulses. Those are shadows of a higher intimacy and pleasure - the kind that existed within the Trinity for all eternity. I believe that these shadows will pass and higher forms of delight and enjoyment and intimacy will the the rule. Moreover, as Jesus is clear there is no giving or being given in marriage in the eternal kingdom, such needs could not be met and would only be sources of frustration.
One more thought: I think we need to be careful not to view everything about humanity in terms of sexuality. It seems there is a trend that way and I'm not sure it's helpful. We do some things not because we're sexual, but sometimes just because we're human. I'm leery of identifying humanity in terms of only, or even primarily, sexuality.