Unless there was an error in meiosis during making of the gametes, each parent contributes the same number of chromosomes. If the offspring has 1 or 3 of a certain chromosome due to an error in gametogenesis, then one parent will have contributed more chromosomal DNA.
Interestingly, because sperm are small and eggs are large and contribute the majority of the cytoplasm, you do get most or all of your mitochondrial DNA from your mother, allowing us to trace maternal lineages.
