It is normal for a normal baby to appear to sit and stand after 6 months of age, and a child can sit alone only after 7 months of age.
For normally developing babies, sitting and standing usually occurs gradually over time. At 6 months of age, babies can hold on to objects around them or use their hands to support their bodies, but they are not stable. By the time the child is 7 months old, he or she is able to sit alone for a few moments.
As the child continues to grow and develop, by 8 months of age, he or she is able to sit very still and turn from side to side. The child will also be able to get off the bed or table by supporting his chest with his hands and crawl on his hands and knees.
The sitting and standing time may vary slightly from child to child, but if there are no other signs of abnormality, it is sufficient to provide guidance and care. If there are other symptoms, it is recommended to consult a doctor to find out the cause of the problem and to rule out the possibility that the child is behind in gross motor development.