When my dad was a kid, they lived in a two bedroom house with one bathroom and the family consisted of him, his two brothers and his mother and father. When I grew up, we have it a little bit better. We had the same sized family as my father did, but we lived in a three-bedroom house with two bathrooms.
How many bathrooms do you really need? Think about it. Here's what I would like to suggest, if you have more money than you know what to do with and would love to help the economy, then you should put as many bathrooms as you need in your home.
If you really need to tell your friends, that you have a 250 bedroom house with 275 bathrooms, and you have the money to pay for it, do it and knock yourself out. However, if you are building a new home, I would like you to consider, this question. How many bathrooms do you really need?
If you want each one of your children to have their own bathroom, then go for it. It will require more cleaning, more money to build these bathrooms and is it really necessary.
Here's what I would suggest as a guideline for deciding, how many bathrooms you really need. One bathroom for two or less people, two bathrooms for five or less people and three bathrooms for eight or less people. You could actually add one bathroom for every three people as a general rule of thumb.
Don't get carried away and start installing bathrooms all over your house, it doesn't make sense. Bathrooms are expensive and I have been in the homes, where I was the only person that used at bathroom. Some bathrooms might not ever be used.