... and physical attributes. And one of the attributes of interest, unsurprisingly, is penis size! The world needs to know more about the strength of the causal chain running in the reverse direction, and Australian researchers are keen to help. But they need more volunteers, and have a site where volunteers can participate in the sudy: men.andmuchmore.com.
One of the instructions is pretty simple:
If possible, please have a tape measure ready. [Bold emphasis in the original]