My main floor bathroom is leaking from the toilet and causing a leakage into the ceiling of the basement bathroom/ This is becoming a real mess and I know absolutely nothing about plumbing. Can any of this be caused from the second floor bathroom. There is no leak on the second floor whatsoever but my dad seems to think its coming from the second floor. Can taking a shower or using the bathroom on the second floor agitate the problem occurring on the main floor or basement. Please help

I would check the wax seal under the toilet first floor,then if that's not the problem,the second floor's wax seal(you will need to check the base of the toilets for any moisture), also feel the water lines from both units,the lines can leak with time(and movement due to use).

Where are the pipes located(drain),Are they on the outside walls?If so,there might have been a rupture in the lines(if it's cold where you are)

I would start with the normal things first,wax rings aren't too bad to replace,they do leak after time and use.Removal of the nuts beside the base,lifting the unit from the floor bolts and removal of the old/replacement of new,reinstalling the unit properly, these are not terribly difficult but do take a little finesse.

Hope this helped.