Some do not want anyone to find out because of embarrassment. Children are often given rewards such as money or candy in exchange for keeping this secret. Other children worry that they will not be believed. If a child does reveal their secret, it usually produces a some backlash in their family as well as in society. Society often blames the victim as well, by insinuating that the child was seductive or by questioning the victim as to why they did not disclose the abuse sooner.
Some children even lie to protect the offender.
If a child does reveal the abuse, it is often between three and seven years after the abuse began. The impact of incest differs from victim to victim and situation to situation. The length of the abuse is a factor in the consequences. Generally speaking the longer the abuse continues the more damage that is likely done. The older the child is when the abuse occurs is another factor.