Voice pitch (fundamental frequency,
F
0
) is a key dimension of our voice that varies between sexes after puberty, and also among individuals of the same sex both before and after puberty. While a recent longitudinal study indicates that inter-individual differences in voice pitch remain stable in men during adulthood and may even be determined before puberty (Fouquet
et al.
2016
R. Soc. open sci.
3
, 160395. (
doi:10.1098/rsos.160395
)), whether these differences emerge in infancy remains unknown. Here, using a longitudinal study design, we investigate the hypothesis that inter-individual differences in
F
0
are already present in the cries of pre-verbal babies. While based on a small sample (
n
= 15), our results indicate that the
F
0
of babies' cries at 4 months of age may predict the
F
0
of their speech utterances at 5 years of age, explaining 41% of the inter-individual variance in voice pitch at that age in our sample. We also found that the right-hand ratio of the length of their index to ring finger (2D : 4D digit ratio), which has been proposed to constitute an index of prenatal testosterone exposure, was positively correlated with
F
0
at both 4 months and 5 years of age. These findings suggest that a substantial proportion of between-individual differences in voice pitch, which convey important biosocial information about speakers, may partly originate
in utero
and thus already be present soon after birth.