This study examined the differences and similarities experienced by secondary school science teachers when teaching science within and outside their area of specialization in single sex and co-educational schools. Interviews were conducted and audio taped for six experienced science teachers on their qualification, classes/subjects taught and teaching experience. To ensure that each teacher's perspective was heard, each interview was reviewed, and agreement about the meaning was built to the satisfaction of the teachers. On analyzing the differences and similarities in the teachers experiences, it was found that those teaching out of their areas of specialization found it difficult structuring their lessons, getting back on track when drawn away from their original lesson plan and were sometimes unable to construct explanation in response to students (especially male) questions. The importance of training more science teachers in specific fields, assigning teachers to teach within their areas of specialization and creating a learning environment that promotes equity is discussed. (Contains 14 references.) (Author)