When deciding which sex might be most suitable for your family, please consider the following:
In general, female Ridgebacks tend to assume leadership roles within the group. Male ridgebacks tend to appear comfortable taking a subordinate role to at least one female within a group.
All Ridgebacks with correct temperaments should be 'aloof'. But don't mistake aloof for lazy. Females specifically tend to be more 'driven'. It is difficult to explain what that means exactly, but some understanding can be gained from the disproportionate amount of female RRs with performance titles (although human-owner behavior can explain part of this as well).
Females tend to 'sound the alarm' more than males, and while hunting, females are more inclined to 'direct traffic'. In the broadest sense, this leaves the males to ‘take care of business' if the need actually arises (which it usually doesn't). That really summarizes the male RR response to most things - fairly laid back until a legitimate need for action arises. Then he'll switch modes, take care of business (and heart-stoppingly quickly), and then switch right back to 'Mr. Happy-Go-Lucky' like nothing happened.
Many long-time Ridgeback breeders agree that male Ridgebacks are easier to raise for first time owners. The females can be more challenging because they are more aware of pack “hierarchy” and in many cases are a little smarter; meaning, they can problem-solve without much input from their owners. You need to stay one step ahead of a bright bitch, because they are always thinking of ways to get what they want, with or without your permission!