The Abel differential equation y ′ = p(x)y 3 + q(x)y 2 with meromorphic coefficients p, q is said to have a center on [a, b] if all its solutions, with the initial value y(a) small enough, satisfy the condition y(a) = y(b). The problem of giving conditions on (p, q, a, b) implying a center for the Abel equation is analogous to the classical Poincaré Center-Focus problem for plane vector fields.Following [3,4,8,9] we say that Abel equation has a "parametric center" if for each ǫ ∈ C the equation y ′ = p(x)y 3 + ǫq(x)y 2 has a center. In the present paper we use recent results of [15,6] to show show that for a polynomial Abel equation parametric center implies strong "composition" restriction on p and q. In particular, we show that for deg p, q ≤ 10 parametric center is equivalent to the so-called "Composition Condition" (CC) ([2, 3]) on p, q.Second, we study trigonometric Abel equation, and provide a series of examples, generalizing a recent remarkable example given in [8], where certain moments of p, q vanish while (CC) is violated.----------------