When is it ideal to have Baby No. 2?

Mypaper 有以下的文章：(copy from mypaper newspaper)

The oft-asked question posed to most married couples with only one child must be this: So, when is No. 2 coming?
      Depending on how the couple feel about expanding their brood, that question can be seen as well-meaning, or simply rude.
      After all, having how many kids - if at all - is a personal matter. And there are many factors to consider: Can the family afford another child? Will mummy have to quit her job to take care of both kids? Is the flat big enough for two energetic tots?
      The rising cost of living, the stress that kids face in school, and the increasingly competitive world are other equally practical considerations. Many working mothers may also find it difficult to juggle a career and a growing family.
      Even if all the obstacles to having No. 2 are overcome, the next question of when ensues.
      So, what does research say?
      In terms of children's relationships with their parents, sibling rivalry and kids' self-esteem, the best time to have No. 2 is when the first-born is aged under a year or over four, studies have found.
      This is because kids aged under one do not have a sense of their exclusive status yet, so they are less likely to resent a sibling, according to Dr Jeannie Kidwell, a professor of family studies at the University of Tennessee.
      Children aged over four have had time to enjoy exclusive attention from their parents, so they are also less likely to reject a new baby, added Dr Kidwell. Besides, most kids of that age would have started to focus more on their own lives, after having formed friendships with peers.
      According to Heidi Murkoff, author of the best-selling pregnancy and parenting series, What To Expect, there are four fundamental questions a couple should ask themselves before taking the plunge for No. 2:
> Do you find yourself longing for kids close in age so that they can be each other's playmates?
> Would you rather have another round of diapering days and sleepless nights sooner than later?
> Would you prefer to space out your pregnancies so that you can enjoy each child's little-kid stage without distractions?
> Do you like the idea of spacing kids far enough apart in age, to minimise the risk of sibling rivalry and of them being at similar developmental stages?
      According to Murkoff, if the answers to the first two questions are "yes", then the couple are likely ready to take the leap. If they answer "yes" to the last two questions, then they should probably wait a little longer.
      Another vital factor that couples should consider is their age, especially for women. If, say, the woman is 38 and wants more than one child, then she probably does not have the luxury of spacing them three years apart, according to San Francisco-based parenting website BabyCenter.
      One other area that couples tend to neglect is whether both are on the same page when it comes to having another child. What if one party is not ready to have No. 2 so soon, if at all? The first step towards resolving that is to talk to each other about it.
      Of course, when to have No. 2 is not based only on science and practicality. Having another child is also about love - what does your heart say? Sure, most couples would weigh the pros and cons of having another baby but, admittedly, this is one decision that is led primarily by the heart.
      Whether the second pregnancy comes soon after the first or several years down the road, adding another bundle of joy is always a cause for celebration for a young family.