Two experiments were conducted to examine the on-line processing mechanisms used by young children to comprehend pronouns. The work focuses on their use of two highly relevant sources of information: (1) the gender and number features carried by English pronouns, and (2) the differing accessibility of discourse entities, as influenced by order-of-mention in a clause. Adults use both evidential sources, as early as 200 ms after the offset of the pronoun (Arnold, Eisenband, Brown-Schmidt, & Trueswell, 2000). We find that like adults, 35-year-old children use a pronouns gender to guide their choice of a referent, and that they use it rapidly on-line. But unlike adults, they show little or no signs of a first-mentioned bias, either off-line or on-line. This is consistent with a tendency for children to initially recruit reliable sources of constraint for language comprehension in this case, the gender of the pronoun.