Pete Wentz doesn't know what the ''key to coparenting'' is.

The Fall Out Boy rocker has 10-year-old son Bronx with his ex-wife Ashlee Simpson, and although they make a good team when it comes to coparenting, he doesn't ''have all the answers'' about sharing parenting duties.

He said: ''[I don't] have all the answers. Telling somebody what the key to [coparenting] is would be insane. I think it's important to listen and to give people balance.''

The 40-year-old musician also has son Saint, five, and daughter Marvel, 17 months, with his girlfriend Meagan Camper, and praised both Ashlee - who also has four-year-old daughter Jagger with husband Evan Ross - and his beau as ''great'' mothers.

He added: ''[Ashlee is] a great mum. [Meagan] is also a great mum. A great person. She's a good balance for me.''

And Pete says there could be more children on the horizon for himself and 30-year-old Meagan.

Speaking to Us Weekly magazine, he said: Maybe [we'll have more kids]. Fill up the guitar [Hard Rock] hotel, you know?''

Meanwhile, the 'Centuries' hitmaker isn't the only one keen to have more children, as Ashlee, 35, and Evan, 31, recently confessed they'd like to have ''a flock'' of kids in the future.

Evan said: ''That's the plan. ... I want a flock.''

Whilst Ashlee added: ''We want another one! Jagger will take care of the next little one. I would like to have another one next year, definitely.''

But Ashlee might have to take some time off before she expands her family, as she previously admitted she is finding it hard being a ''working mum''.

The 'Pieces of Me' singer said: ''Music is a career by itself, having a clothing line is a career by itself, having a shoe line is a career by itself, being a mum is a career by itself. It's definitely overwhelming.''