The ABO system has three alleles: A, B and O. A and B are codominant; O is recessive. The tool builds every possible genotype combination of the parents (assuming the standard most-common genotype for each phenotype) and counts the resulting child phenotypes. The Rh factor works similarly: Rh + is dominant, Rh − is recessive. Because parents' hidden genotypes matter, the table shows probabilities — a child of two "A" parents, for instance, can be A (about 93.75%) or O (about 6.25%).
ABO 系统有三个等位基因：A、B、O。A 与 B 为共显性，O 为隐性。本工具枚举父母各种可能的基因型组合（按每种表型最常见的基因型假设），统计后代表型。Rh 因子同理：Rh 阳性为显性，Rh 阴性为隐性。由于父母的隐性基因型存在不确定性，结果以概率呈现——例如两位 A 型父母的孩子约 93.75% 为 A 型、约 6.25% 为 O 型。
