In all seriousness:
[sblock]It seems there are four aspects to this question, and most of the answer is at the discretion of the DM's opinion concerning Warforged nature, personality, purpose, and design:
- Can a Warforged love?
- Can a Warforged lust?
- Can a Warforged stimulate others sexually?
- Can a Warforged receive sexual stimulation?
Questions 1 and 2 are related to Warforged emotional capability and range. I imagine this would depend on the "programming", so to speak, of the Warforged. It's clear from generic D&D material that Warforged have more fully developed personalities than their creators originally intended.
Concerning Question 1, it seems love is quite the possibility, if a DM allows such a peculiar bond to form between a living organism and a machine. And if they can love, they can certainly see the appeal of strengthening that bond via the Question 3.
Lusting is a different matter, since its impetus is largely tied to Question 4.
Question 3's answer is easily yes, though the extent to which this can occur would vary largely depending on what sort of physical design they have, including different components and their shape, size, material, and function (e.g., vibrating or warming).
Which brings us to question 4. Given standard D&D assumptions about them being created for war, it's safe to assume they weren't created with any sort of genitalia. However, as with any anthropomorphic creations we have, they certainly could be given them, at the time of creation or at some point afterward. Whether said genitalia also have any sort of pleasure receptors would also be a different consideration. But if they do, it's safe to assume a Warforged with such components would have an incentive for using them, hence the relation to the lust question above.
Notice that I didn't mention procreation. Remember that infertile people can fall in love and have sex, so that shouldn't be an issue in and of itself. Love and sex don't have to be tied to procreation, they just typically are since that's the sort of creatures we are. At least, that's my 2cp.[/sblock]
In short, it's up to the DM, but I imagine WOTC's official answer would be no.