It may be both. It depends on what is causing the abnormality. For instance, old (hypogonal) men tend to go through what is known as "andropause" -- their T levels go down and their estrogen (estradiol, E2) levels skyrocket. In fact, they may have less T and more E2 than women of the same age!
E2 is created from T by an enzyme called aromatase. Hence, inhibition of this enzyme will increase T and lower E2. In fact, some people think that as men get older their aromatase enzymes become more active or perhaps increase in number -- leading to the low Ts and high E2s.
But since E2 is metabolized from T (which is turn is made from cholesterol), a low T can lead to a low E2. For instance, if you went on a zero-fat, zero-cholesterol diet -- you'd probably notice that both your T and E2 levels would decrease a bit.
There are many factors at play here, but the T/E2 ratio, obviously, is what is most relevant when talking about hormonal balance.
D.
