There is a possiblity that they can mate and produce a child, but since a werewolf and a vampire can kill eachother it is highly impossible. And, the risk that they can reproduce is extremely dangerous, a werewolf can kill a vampire and a vampire can kill a werewolf, vice-versa. I do know that alot of authors can play around with the rules of both vamps and weres and create there own unique taste to it. In my vampire series I gave purebred vampires a chance at having a child... though I don't want anyone to take it so that is the only bit I'm sharing.
Also, as I said before, werewolves and vampires aren't always that great of friends, and since Renesmee is a half vampire half human she may get the urge to bite Jacob, therefore, putting herself at risk of potentially dying from what she did. And yes, a hybrid can also as well die just like there parents who could now be a turned vampire and already vampire.

If you want to know more, just ask me or go to google and study a lot more of Renesmee and Jacob being able to have a child. I'm a fan of them being a couple too! :)