I know that a child's things really belong to his father (although help with a source would be appreciated). However, the same is generally true of a wife's property/income belonging to her husband, yet, under certain circumstances, a wife can retain her property, and in other cases a husband can give property to his wife (more source help required!). My question is, can a father give something to his young child, or is ownership utterly meaningless until a certain age (and, if the latter, is that age majority, or sometime slightly before majority)?
It is certainly possible to transfer ownership of an object to a child. One place this is made clear is in the Gemara (Sukkah 46b) which says that one should not transfer possession of his lulav to a child on the first day of Sukkos. The reasoning is that the child is not of legal age to transfer it back, and therefore the adult will not be able to perform his own obligation, as the first day's obligation requires a lulav one owns. This represents normative Halacha as codified in Shulchan Aruch OC 658:6.
As for the age of the child - I cannot source this offhand but I believe it is possible to transfer ownership of an item to any just born child, through zechiya. This is the legal concept which says that anything which is a beneficial to a person can be done without the person's knowledge, since there is an assumed will of the person. Since the only real potential issue with a minor acquiring something is lack of the requisite awareness, one can effectively establish oneself as the minor's agent and make the acquisition on the minor's behalf even without the minor's saying so, using the mechanism of zechiya.
Furthermore, the aforementioned case about the lulav itself is clearly talking about a child who is even younger than the age of six - the age when a child presumably understands the basics of business dealings (see Shulchan Aruch CM 235:1), because for ages six and up the SA cites a view that maintains that the whole thing isn't relevant since such a child might legally be able to return the lulav. Clearly then, the blanket statement, "one should not transfer ownership of his lulav to a child," refers even to children under the age of six.