Question-asking is a basic skill, required for the development of scientific thinking. However, the way in which science lessons are conducted does not usually stimulate question-asking by students. To make students more familiar with the scientific inquiry process, we developed a curriculum in developmental biology based on research papers suitable for high-school students. Since a scientific paper poses a research question, demonstrates the events that led to the answer, and poses new questions, we attempted to examine the effect of studying through research papers on students' ability to pose questions. Students were asked before, during, and after instruction what they found interesting to know about embryonic development. In addition, we monitored students' questions, which were asked orally during the lessons. Questions were scored according to three categories: properties, comparisons, and causal relationships. We found that before learning through research papers, students tend to ask only questions of the properties category. In contrast, students tend to pose questions that reveal a higher level of thinking and uniqueness during or following instruction with research papers. This change was not observed during or following instruction with a textbook. We suggest that learning through research papers may be one way to provide a stimulus for question-asking by high-school students and results in higher thinking levels and uniqueness. (Contains 3 tables.)