Yes, Men and women have different energies and hence vastu will act - or affect - men and women (in the same house) in a different way.
Absolutely not. Nor is it a philosophy. Its natural science which brings Peace, Prosperity and Happiness.
A defect is a defect. A remedy will try to eliminate the ill-effect of the defect.
One of the simplest tests is to take a new born baby in the house. If he starts to cry then the house has bad vastu.