There is a ton of data showing that children born out of wedlock are at much greater risk for poverty, poor educational attainment and a host of other ails. This will not apply to Christina Aguilera's child because of the Christina's wealth and fame. However, Christina is a role model and her actions could send the wrong impression to young girls. Christina should set an example.
The primary benefit of following the established order of marriage before procreation is that it allows for greater financial stability before child rearing. Christina Aguilera is in a position of great financial stability, so there is no need for her to marry before having more children. This ignores the issue of whether or not a third party has any right to make this judgment for her (we don't).
No, having children out of wedlock no longer has a stigma attached to it. Society has changed. It is no longer frowned upon for unmarried women to have children. Marriage is not as popular as it once was. Younger people today do not feel a need to make the marriage commitment and I support them in this.
Why should she? From a financial standpoint it makes no sense as unlike most people she is rich and has more to lose by getting married. Also, I never bought into the concept that getting married means you love the person more than a couple who is not married. If Christiana wants to put off marriage so be it and it is her choice to make.
Christina Aguilera is a financially sound woman who has the ability to afford the best things for her children. It is unnecessary for her to subscribe to the antiquated custom of marriage in order to justify her having a child to society. Through her various celebrity roles, she has built up a small empire for herself. Thus, she has the ability to provide anything a child may need from basic amenities to developmental opportunities that many Americans can only dream of.