If by "It's possible" you mean "there are products that will claim to do this", they you're right. If by "It's possible" you mean "it fundamentally is, was, or ever will be possible to control by technological what happens to a document once it's in someone else's hands", then no, it's not possible.
There are products that will produce PDFs that essentially have a little "don't print me" flag in them. But then you have to rely on the fact that the person you're sending to doesn't know to simply open the PDF in a viewer that ignores that flag, or to run it throught some software that strips off the flag.
DRM can never work, as long as users control their own computers.
Interestingly, there is some speculation that this is why Apple is moving to Intel chips - precisely to prevent users from controlling their own computers. Intel's upcoming chips will have support for DRM right in hardware, meaning that it will be next to impossible to fully control your own computer.
I hope this isn't true, but given the recent failures of things like the iTunes DRM, you never know...
