Circision because father had it?

Im doing a psychology project and part of it involves yzing the reasons for circision, and one of them, being "because his father is cut" i dont understand the reasoning behind it, can someone explain it to me because to me it sounds like a selfish barbaric act in which you are cutting of your child's body part in order to justify(?) his father's own mutilation? I mean honestly, can someone say a straightforward answer of why it is logical and practical to cut off a body part to look like the father? I mean it seems illogical and baseless,... but hey I could be wrong....