Continuum: A continuum is a range or sequence with no clear divisions. In this case, it would refer to the spectrum of family support for transgender individuals.
Gradient: A gradient refers to a gradual change in something over a distance or time. It could describe how family support for transgender individuals can vary gradually from low to high.
Spectrum: A spectrum represents a broad range or variety of something. In this case, it would represent the range of possible levels of family support for transgender individuals.