No, they can still vote while in jail.
Maybe in Netherlands they do lose the right to vote.
What does Netherlands have to do with the topic? Why was it mentioned.... like why.... Netherlands???
BTW In Norway it depends on the type of prison, but closer to the end of the time you are supposed to spend there, people are transferred to "open jail". That is when inmates usually get a real job and go to prison after work, go home to families on saturdays, christmas, etc... That would be a perfect opportunity to impregnate someone... like Varg Vikernes did during his time. Now he is out on parole and has 2 kids and one more to come.
Oh and in Norway you have the right to vote, because even in jail you are still a citizen.... providing that you are... something that is quite rare in Norwegian prisons nowadays. Usually muslim rapists and eastern european thieves in there anyway.