i would go for a male i have had several betta's and i really have only seen male bettas sold at our local betta shops, also if you do choose to get one of each or even 2 male make sure to have them in seperate tanks or they make a special tank for betas that is one tank but seperates in the middle so they have no contact and its inexpensive
To have male and female bettas together you need a large tank with lots of vegetation and places for the female to hide. Except when mating male bettas will kill females. Putting a male and female together in a small tank will have the same result as putting two males together. They will fight to the death.
Get a male the colors are brighter and they are more pretty ^^ I have a male blue betta named Fighter ^^ he is a stunning deep blue with black head.
Males because they are very pretty, but if you are wanting them to have babies youll nned both :)
Male..more colors to choose from..female only comes in brown
Get both and put them together in a tiny tank.
i ment pet shops lol