When one seems much better than two

Better communication

Once the mother becomes pregnant, no mater how old the child is, it is important to tell the firstborn about it in a calm way, she says, and the same applies to informing the child about a miscarriage.

Even a child less than 1 year old can detect changes in the family dynamics, Yan says.

If parents fail to communicate with a child frankly, he or she will pick up what is happening, and will probably feel confused, fearful, stressed and lonely.

However, it is unwise to talk too frequently in the presence of the firstborn about the happiness the second child will bring to the family. The key is to let the firstborn understand there will be a new family member and that the family as a whole will need to adapt to the change, Yan says.

Most firstborns have mixed feelings about a prospective sibling, and a second child introduces competition for resources, which is usually fiercer in low-income families.

It is understandable that the first child will have negative emotions and reactions, but sibling rivalry is good experience for a child's long-term development, such as for the child to learn to share.

It is wrong for parents to want their firstborn to have no negative feelings about the sibling, because such expectations will put pressure on the first child, and will probably cause the first child to suspect parents do not love him or her, and that the sibling will replace the child's position and deprive him or her of love from the parents, Yan says.

Also, such negative feelings, including anger and envy, are all a part of life, and having them in relation to a sibling gives the older child the chance to experience such feelings and learn how to deal with them with support from parents, she says.

Age gaps

Age gaps also influence the attitude a first child has toward a second child, but the ultimate factors are the parent-child relationship and parent-parent relationship.

For example, children aged 3 to 6 start to experience and deal with the fact that a person's affection is often not exclusive. A child in this age group when a sibling is born is likely to feel stronger sibling rivalry, especially if the parents fail to guide him or her properly.

But if the child has a good relationship with its parents, competitive emotions he or she feels are likely to turn into a desire for self-realization, and the first child will become a good brother or sister, as with Wu's son.

"Many parenting problems appear to arise when a second child arrives but in fact genesis of these problems is an unhealthy relationship between parents and the first child before the second child arrives," says Yan.

"What really matters for families raising a second child is the quality relationship among family members."

Having a second child is also a good opportunity for the first child to be educated about sexuality, says Liu Wenli, an sexuality educator and brain science expert at at the School of Brain and Cognitive Sciences of Beijing Normal University.

Liu's team has developed comprehensive sexuality textbooks at different levels for preschoolers and primary school students.

Parents should not conceal the nature of pregnancy and birth to the children, but should explain it in simple and straightforward terms to give the man objective and scientific understanding of howa child is conceived and born, and what sex is, which will be of lifelong benefit to the child.

Contact the writer at liuzhihua@chinadaily.com.cn