On a standard PC: Serial Ports are male connectors, the cables are female. LPT ports on a computer are female.
It's 2012, and I still have to learn more about serial ports, now and then...
When looking for PCIe (or PCI or USB) to serial port add-ins or adaptors look out for the voltage. Most USB adaptors produce +5/-5 volts. "Good" add-in cards output 12V on the RS-232. Apparently, the standard is anything up to 15V. But, lower voltages have potential compatibility issues.
tags: ports, serial, RS-232