Table 1.

Comparison of normal and FCG mice

Mouse cross	Nomenclature	Genotype	Gonadal phenotype	X	Y
WT	F	XX	ovaries	2	0
	M	XY	testes	1	1
FCG	XXF	XX	ovaries	2	0
	XYF	XY-	ovaries	1	1
	XXM	XXSry	testes	2	0
	XYM	XYSry	testes	1	1

In the FCG, numbers of X versus Y chromosomes can be separated from gonadal effects.