Updated by: Arabinda Naik
This theory was proposed by Calvin Bridges. From his study on Drosophila the X chromosomes carry factor for femaleness whereas autosomes A carry genes for maleness. Y chromosome does not take part in sex determination. If X/A ratio is 1.0 the offspring develops into female. But if it is 0.5 then the offspring develops into male. If the ratio intermediate between 1.0 and 0.5 the resultant individual is neither a male nor a female. If ratio is 1.5 it is super female and if ratio is 0.33 it is super male.
Chromosome complement X/A ratio Sexual morphology
XX + 2A 2/2= 1.0 FEMALE
XX + 3A 2/ 3 =0.67 INTER SEX
xy + 2A 1/ 2 = 0.5 MALE
XO + 2A 1/2 = 0.5 MALE
XY + 3A 1 /3 = 0.33 META MALE OR SUPER MALE
XXX + 2A 3/2 = 1.5 SUPER FEMALE OR META FEMALE
XXX +3A 3/3=1.0 FEMALE
XXX + 4A 3/4= 0.75 INTER SEX
XXXX + 4A 4/4= 1.0 FEMALE.