Yes, this is true. When playing co-ed indoor volleyball (also called Mixed Six), anytime your team has more than one hit, one of the hits, not including blocking, must be made by a female.
There is also a provision in the rulebook for "reverse co-ed" (reverse Mixed Six) where one of the touches must be made by a male.
From the 2013-2015 Domestic Competition Regulations, Co-Ed Rules (page 108):
1.2 When the ball is played more than once by a team,
a female player shall make at least one of the contacts. Contact of the ball during blocking shall not
constitute playing the ball. There is no requirement
for a male player to contact the ball, regardless of
the number of hits by a team.
1.2.1 If a team contacts the ball more than one
time during offensive action, one of the
contacts must be by a female player, but
there is no restriction preventing all three
team hits from being made by female players. Contact of the ball during blocking action does not count as one of the three team
hits. Therefore, after a block, a male player
may play the ball back over the net as such
contact would be considered the first team hit.
1.2.2 A ball contacted more than once by a team,
without a female player having contacted
it, remains live and does not become an
illegal hit until it fully crosses the plane of
the net or is contacted by an opponent.
1.2.3 An illegally hit ball blocked by an illegal blocker
results in a double fault, and a playover is