Final answer:
Anatomically modern human siblings can indeed have a significant age difference of three decades, influenced by factors like adoptive relationships, half-siblings, and parental choices in family planning.
Step-by-step explanation:
Yes, anatomically modern human siblings can have a three-decade age gap. In certain situations, such as when there is a large span of years between the births of children within a family, it's possible for siblings to have an age difference that could span three decades.
Factors such as adoptive siblings, half-siblings, and second marriages can contribute to significant age differences between siblings. Furthermore, variations in parental age at the time of each child's birth, and the family's choice regarding the spacing of children, can lead to large age gaps. It's not uncommon in modern society for individuals to start or expand their families later in life, which can also result in substantial age differences among siblings.
Overall, societal changes, advancements in fertility treatments, and shifts in cultural norms regarding family planning have made it more feasible for siblings to have a wide range of age differences. It still remains a less common occurrence but is within the realm of possibility in human biology and family dynamics.