Abdulla - since you want a single crossover point in your list of variables, then using crossoversinglepoint seems like the correct choice. To use this function, you will need to set the GA options using gaoptimset. Something like the following would probably work for you
options = gaoptimset('CrossoverFcn',@crossoversinglepoint);
Note that you can set other properties of options as well, so you are not limited to the above single option.
