Abstract: The invention provides methods for identifying an infant or child predisposed to develop symptoms of short stature, or an adult capable of genetically transmitting a predisposition to develop short stature to an offspring. The methods comprise analysis of a region of DNA in the genome of a subject located at or near a site called FRAXG on Xp22.1. In one embodiment, the analysis comprises determining the number of (CGG)n/(CCG)n nucleotide triplets within FRAXG. In another embodiment, the analysis comprises determining whether there is hypermethylation within the CpG island encompassing FRAXG. The invention also comprises probes and primers for use in the above analyses, kits containing the probes and/or primers for performing the analyses, and cell lines containing high numbers of (CGG)n/(CCG)n nucleotide triplets within FRAXG.