Which sex is homogametic in side-blotched lizards?
Lizards of the genus Uta are apparently male heterogametic (XY) (Pennock et al. 1969). The XY system seems to be the most common mode of sex determination in iguanid lizards (Kasahara et al. 1983).

Kasahara, Y et al. 1983. Chromosome mechanisms of sex determination, G- and C-band patterns and nucleolus organizer regions in Tropidurus torquatus (Sauria, Iguanidae).  Genetica 60: 151-156.
Pennock, L.A. et al. 1969. Minute Y chromosome in the lizard genus Uta (Family Iguanidae). Cytogenetics and Genome Research 8: 9-19.