The most anterior part is the rostrum.
R B Bean, a Philadelphia anatomist, suggested in 1906 that the "exceptional size of the corpus callosum may mean exceptional intellectual activity" and claimed differences in size between males and females and between races, although these were refuted by Franklin Mall, the director of his own laboratory.
Of much more substantial popular impact was a 1982 Science article claiming to be the first report of a reliable sex difference in human brain morphology, and arguing for relevance to cognitive gender differences. This paper appears to be the source of a large number of lay explanations of perceived male-female difference in behaviour: For example Time magazine was reported to state in 1992 that the corpus callosum is "Often wider in the brains of women than in those of men, it may allow for greater cross-talk between the hemispheres—possibly the basis for woman’s intuition. There is scientific dispute not only about the implications of anatomical difference, but whether such a difference actually exists. A substantial review paper performed a meta-analysis of 49 studies and found, contrary to de Lacoste-Utamsing and Holloway, that males have a larger corpus callosum, a relationship that is true whether or not account is taken of larger male brain size. Bishop and Wahlstein found that "the widespread belief that women have a larger splenium than men and consequently think differently is untenable." However, more recent studies using new techniques revealed morphological sex differences in human corpus callosum. Whether, and to what extent, these morphological differences are associated with behavioural and cognitive differences between males and females remains unclear.
Corpus callosum abnormalities in women with borderline personality disorder and comorbid attention-deficit hyperactivity disorder
Nov 01, 2007; Objective: Decreased brain volumes in prefrontal, limbic and parietal areas have been found in women with borderline personality...
ARX and SHH gene mutation analyses revealed no mutation in patients with agenesis/ dysgenesis of the corpus callosum
Apr 01, 2010; Abstract. Mutations in sonic hedgehog (SHH; OMIM *600725) and the aristaless-related homeobox gene (ARX; OMIM *300382) can both...