There seems to be a lot of confusion concerning this question. The following text (provided by Netrunner) should provide a better understanding of the situation.

Firstly we have to make a distinction:

a. Reps have programmed emotional responses that are built in to make them seem like Humans. These are not real emotions and the Reps don't *feel* them - they are simulations of the responses that Humans give. These are what allow Reps to interact with Humans and help them to appear Human.

b. Some Nexus 6 Reps have started developing their *own* emotional responses. And these *are* real emotions. It is the first stage to the eventual possibility of them developing empathy (as we see in Roy at the end).

The V-K test measures a number of physical responses to the questions. These add up to a measurement of empathic response. The Reps respond with answers and programmed physical responses. Humans respond naturally. I am sure there are aspects of the test that I "don't know" but certainly one aspect is, for example, not just measuring things like how much of a blush response there is, but the speed at which it happens. Reps and Humans have the same basic responses, but at different levels and speeds. (Note that the V-K machine predates Nexus 6 Reps and was designed to identify Reps that had no true emotional responses of their own, hence the question of whether it will still work in identifying Nexus 6 Reps.)

There may also be some questions that allow Reps to make mistakes. For example (from DADoES), "Your husband hangs a picture on the wall of a naked girl lying on a bearskin rug - how do you respond?" Well, if you're a human in this post-apocalyptic world, you respond to the fact the rug is bearskin and ignore the naked girl part. If you're a Replicant, you might miss that point.

Can replicants reproduce?

We are never told whether or not they can, but it makes sense to assume that they cannot. It would just create too many problems and bad publicity for the replicant "manufacturers" if they could:
- People could breed their own replicants, so Tyrell would make less money.
- The replicants are viewed as commodities, not as human beings. But what if they start having children? Could they still be regarded as less-than-human commodities instead of real people?
- How would the public react to babies of parents that die after 4 years, and are thus unable to take care of their offspring? Would the newborn itself live longer than 4 years anyway?

Can replicants become intoxicated?

There is no evidence that they do, though this is not proof they can't. Unless they specifically have a way to quickly metabolise alcohol, then being biological, alcohol must eventually affect them. They obviously do drink alcohol as a bottle can be seen in the reps' apartment in Leon's photo. This is ignoring the possibility of Deckard being a replicant, but again, although there is plenty of evidence that he drinks a lot of alcohol, it is arguable whether he actually gets drunk or not.