I have to disagree...not a simple answer.
There are many variables to look at, exaust fans, boiler vents, Ductwork if you have any, insulation in your house, dryers, and fireplaces.Does your heating system or hot watwer heater alreday have a backdrafting issue?/ who knows??
Not to mention all the other air leaks at doors, windows, and other points of entry. Lightswitches, electrical outlets, sill plate insulation and radon gas mitigation systems.
ALL these things come into play on your home,,,yes even the architecture is a factor, ranch, 3 story or split level?
Air is always moving through your home with use also, doors and windows open and close, even the tempurature outside compared to inside matters.
Is your house ballon framed?? Is the air traveling up through the walls and carrying the moisture with it? Adding a vent hole will only add to the problem.
Get a reputable company , HVAC that does blower door testing, or even a building performance person over there to give you the advice you need....heck...we don't even know if you already have water leaks in your basement you don't know about.
Good luck, hope this helps.