It's an area where different people do thhings differently"
A person cannot move his limbs (traditional way)
A person cannot move his or her limbs
A person cannot move their limbs
I use 'their' because its quicker and simpler when referring to a singular person of either gender. There are those who argue that it is numerically inaccurate, but I think this is an oversimplification of singular/plural in English ('everybody' has a plural meaning and tkaes a singular, etc).