From what I assume,
Since Data is an Android, he has no need or desire for Biological practises such as Sex...Even with an Emotion Chip, its not going to make him Human, Data does not require Sleep, Food, Drink or even the Toilet (although from what we've seen, neither does anyone in Trek!)
Data does experiment with Human concepts such as the ones i've listed, however this is merely to help him understand "Human" behaviour. The Emotion Chip does that provide him with Emotions, per say, instead he is provided with Simulated Emotions that work based on the situation he is in and the experiences he has acquired from witnessing others behaviour in similar situations
IMO Data does understand Emotions, he is just incapable of feeling them, he knows from his experience with Humans how to govern an Emotional response and IMO this is the closest he gets to actually feeling himself, why else would he not have the Emotion Chip permanently hoked up to his Positronic Net? Simple, the Emotions he feels aren't real, again they provide him with a greater understanding of Humanity but don't actually allow him to feel anymore Human than he already does, because they are simulated reactions programmed with generic reponses and don't contain the wide range that Humans experience
Data has expressed a desire to Reproduce, he even does so, albeit unsuccesfully in TNG's "The Offspring", I think this is the closest thing to Sex as far as Data is concerned, sure, he may have engaged in the act on occasions, but Sex with Data, is no more emotionally bound than Sex with a Dildo!!