Is there a bonus bias on Wall Street?

Financial writer Shelby White posed an interesting question to the wise girls at wowOwow.com, and we wish to ask the same question to the smart and savvy readers at WalletPop:

Is there a bonus bias on Wall Street?

White argues that although it's hard to find statistical data that lays out bonuses by gender, there's proof that women on Wall Street earn just 55.4% of what men on the same Street do.