Why can't/don't i remember large portions of my childhood?

What age?: Many folks remember little before pre-school, except for very emotional events. If the lack of memory goes well into grade school it may have something to do with lack of motivation to remember or maybe even some trauma that you'd rather not remember. A clinical psychologist can help you sort that out. If the latter is the situation he/she can help you possibly recall or live peacefully w/it.