Yes it is normal - babies go through stages where they prefer one parent over the other. They usually prefer the parent with whom they have the most daily contact (or the parent who is most relaxed with them). This is only a temporary phase. It can be as short as a few weeks, although it sometimes lasts for months and in some cases the child may continue to prefer one parent even for the first 3 years of life. However, when the baby gets out of the baby phase at last, he or she becomes a child who will welcome the attention of both parents. Sometimes the child's preference actually changes for the other parent (again, this is usually temporary). During these developmental "shut outs" your job is to continue to spend time with and near the baby as much as possible in a way that respects the baby's wishes as much as possible. Don't force yourself on the child unless circumstances require it (i.e. your wife isn't home and you are the one in charge or your wife needs rest or is otherwise occupied and you are the one who must take over). When possible, just go with the child's preference saying something like, "oh, you want Mommy now? I'll get her for you." This builds a relationship of trust with the child even in babies who don't yet understand language. Your sympathetic and understanding attitude will pay off later.
Sarah Chana