Here's how you can change Siri's gender to hear a male voice in iOS 7.
1. Go to Settings.
2. Go to General.
3. Go to Siri.
4. Tap on the Voice Gender option.
5. Tap on the Male option.
Siri will now use a man's voice when speaking to you. Note that you can always switch Siri back to the female voice later on if you prefer.