Medically reviewed by Matthew Wosnitzer, MDMedically reviewed by Matthew Wosnitzer, MD Genetics plays a significant role in ...

Scientists have created a 6-legged mouse embryo with an extra pair of hindlimbs at the expense of their external genitalia. But far from creating a monster, this rudimentary rodent provides important ...

A new study in Nature shows that when pregnant mice don’t have enough iron, their (usually male) fetuses with a Y sex chromosome sometimes develop ovaries instead of testes. In other words, ...

A micropenis is a penis that is 2.5 standard deviations smaller than the average penis for a person's age. In adults, it is regarded as a stretched penis length of less than 3.67 inches. Micropenis is ...

Keersten Fitzgerald does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations ...