Parents in Sydney's inner west are calling for a co-educational high school option for their kids, saying it "seems crazy" that they are surrounded by single-sex state schools.

The P&C at Summer Hill primary, where local students are zoned for single-sex high schools, conducted a survey of more than 600 parents in the wider region and found that 89 per cent would prefer a local co-ed school.

"A significant number of parents commented that they were considering moving or had already moved their children from public to private or Catholic schools, specifically to access co-education," the P&C's report said.

Families wanted to support the public system but regarded the lack of a mixed gender option as a barrier, said parent Lassity Martin, who has two sons. "All the primary schools in our area are flourishing because they are all co-ed, and at high school people are forced into these crazy choices," she said.