Five jumbled up sentences (labelled 1, 2, 3, 4 and 5), related to a topic, are given below. Four of them can be put together to form a coherent paragraph. Identify the odd sentence and key in the number of that sentence as your answer.

The correct answer is:
"The evidence for a biological basis for gender certainly doesn’t mean we should be complacent in the face of sexism."

Step-by-Step Explanation:

To identify the odd sentence, we need to find the common theme connecting the other sentences and construct a coherent paragraph from them.

1. Identifying the Core Theme:
Three of the sentences focus on the scientific consensus regarding the nature vs. nurture debate in gender studies, the public discomfort with biological explanations of gender, and the political backlash researchers face as a result.

2. Connecting the Coherent Sentences:
• "Many people are uncomfortable with the idea that gender is not purely a social construct." - This sentence introduces a common public perception and discomfort regarding gender theories.
• "No known real researcher of human behaviour would say that gender is all nature or all nurture." - This established scientific view serves as the "empirical truth" that gender is shaped by a mix of biology (nature) and environment (nurture).
• "Despite this empirical truth, researchers who study the biological basis of gender often face political pushback." - The phrase "this empirical truth" directly links back to the previous sentence (that no researcher claims gender is solely nature or nurture). It explains that despite this balanced scientific view, researchers still face political resistance due to the public discomfort mentioned earlier.

3. Identifying the Odd Sentence:
The sentence "The evidence for a biological basis for gender certainly doesn’t mean we should be complacent in the face of sexism" introduces a moral and political stance against sexism. While it shares the general topic of gender biology, its focus shifts from the discussion of scientific consensus and research pushback to a prescriptive warning about sexism. Therefore, it does not fit into the logical flow of the other sentences and is the odd one out.