The prevalence rates often seem to be overestimated - national samples show that only a minor part of pedosexual contacts happens within the close family: 15% for females, 4% for males.
Incest seems to be much more problematic than other pedosexual relations, because of the special power relation between children and parents.
But, nonetheless, research shows that there is no reason to view incest in itself as very different from any other kind of sexual relationship in general; everything depends upon the conditions under which it all takes place. Volitional incestuous relations are often beneficial for the child. On the other hand, non-consensual incestuous relations may be much more harmful for the minor compared with such relations outside the family.
As in other pedosexual relations, not only the adult initiates the sex.
There are few reliable data on sex between mother and son.
It is not rare for mothers to experience complete orgasm from their babies' breast-suckling; many feel troubled and guilty over this quite normal phenomenon (Haeberle 1978, p.87; Moeller 1983, p.19; Bieber 1962, p.52; Cohen-Matthysen 1982, p.37; Presland 1981, p.77). (see Brongersma 1990 p. 48)
Father/son relationship is in general markedly different from father/daughter incest. Girls tend to respond in an overwhelmingly negative manner, while boys have much more positive feelings. The girl is usually a substitute, which points toward a pseudo pedophile situation. Few fathers or mothers are real pedophiles, therefore the sexual attraction inspired by their offspring will tend to increase with the opposite-child's growing up. Father/son incest, on the other hand, might more often be caused by real boy-love and will thus lessen as the son grows older. (see Brongersma 1990 p. 48-51)
As in the general case of pedosexual relations, there are a lot of considerations which do not even try to distinguish consensual and nonconsensual relations. See f.e. a feminist view. Here we have a single scheme, often based on the own experience, and all incest cases will be pressed into this scheme.
But, in sexual relations this is not possible. What is outrageous for one person, may be very exciting for another. To try to press all experiences into a single scheme leads only to frustration.