You will be surprised to know that according to American traditions, the bride's family pays for the wedding! Well, not for all of it, but for the biggest part for sure.
If you are a father of a daughter, be prepared to pay for the engagement party, the entire reception (including the location, food, and drinks, entertainment, decorations, all the rental items, and of course, the wedding cake). You also have to cover the costs of the bride's dress, accessories, and veil, her flowers, and the bridesmaids' bouquets, photographers and video services, the wedding gift for the couple and what not.
It doesn't mean that the groom's family doesn't spend anything, but it goes without saying that it's a way less! They are responsible for the groom's attire, his gift to his groomsmen (if he wants to), the rehearsal dinner costs, transportation and accommodation for his part of the family, and, in some cases, for the honeymoon.
As you can see, the tradition is not fair to the bride's family. However, do not despair if you have a daughter and live in the USA, because the lines of who pays for what at a wedding are not so distinct now. If your daughter, for example, is marrying a man from a rich family (and let's hope she is), he might offer to cover all the costs. It all depends on the families and financial situations. In many cases today the couple wants to cover a big chunk of expenses, as they don't want their parents to take out a mortgage to pay for everything. So, it's better to get together, talk, and decide WHO IS GOING TO PAY.