Guppy writes: A recent paper appearing in PNAS (Paywalled) measured Testicular volume and Testosterone levels in fathers of children aged 1-2 years. This information was compared against parenting surveys reported by the children's mothers, as well as MRI imaging of brain activity in the men's Ventral Tegmental Area (VTA), taken while the men were viewing photographs of their children.
The results appeared consistent with past studies hinting of correlation — both Smaller Testicles and lower testosterone levels were found to correlated with both greater reported Nuturing-type behavior, as well as greater stimulated VTA activity. The authors commented that further research was required, given the limited scope of past investigations into the subject, saying "Testicular imaging is sort of a unique niche right now."
Guppy writes: "A previous story reported widely in the media, and appearing both on Slashdot and XKCD described a novel cancer treatment, in which a patient's own T-cells were modified using an HIV-derived vector to recognize and kill leukemia cells. In a follow-up publication, a further development is described which allows for a nearly unlimited choice of target antigens, broadening the types of malignancies potentially treatable with the technique."