Well, to depict biology in cartoons, you could start with basic concepts. Maybe show the life cycle of a plant, from seed to full-grown. Or illustrate how different animals adapt to their environments. Use bright colors and fun shapes to make it engaging.
There should be no sex content in kids' cartoons. The industry has strict guidelines and standards to protect children from such inappropriate themes. Cartoon creators are well aware of their responsibility to provide innocent and educational entertainment for kids.
I think having a clear theme and a good understanding of the topic you want to convey are essential. Also, strong drawing skills and the ability to use humor or satire effectively can make the cartoon stand out.