If there are boybands and girlbands, there are groups which has male and female members. The list I made includes groups without instruments, either doing pop, R&B and hip-hop, as long as they were a vocal group.
ABBA- They were the most popular and the biggest selling in their genre. With two males and two females, their formula even extends until the present time and some pop groups even tried to be like them.
Ace of Base- Also from Sweden, they seemed to become the next ABBA (with two males and two females) but their first success was not sustained. They were known for their biggest hit “The Sign”.
The Fugees- This American hip-hop group became famous with their LP “The Score” as well as their version of “Killing Me Softly”. Consists of Wyclef Jean, Pras Michael and Lauryn Hill, all of them had solo successes.
Aqua- They came from Denmark, this group became popular through “Barbie Girl” and a huge debut album. The group had Lene (the only female member) and Rene as leads. They have two other male members.
Steps- With two male and three female members, their sound is somewhat similar to ABBA. Their song “One for Sorrow” sounds a duplicate of an ABBA song. Their success is limited though.
S Club 7- The group consisted of four ladies and three gents, their music which predominantly pop just like Steps as they were both from UK. They first became popular through a Disney TV show which was shown worldwide. Their biggest hit was the ballad “Never Had a Dream Come True”.
A-Teens- They became popular as a tribute group for ABBA, their first LP contains old hits from ABBA and was successful particularly in Europe.
City High- This group is a reminiscent of The Fugees which this group was completely formed by former Fugees member Wyclef Jean. The group scored two top 20 hits in US.
Black Eyed Peas- Originally a group without a lady, Black Eyed Peas had finally signed Fergie making them one of the biggest groups since 2000. They spanned four multi-platinum since then.