Yes! Many agencies in the U.S. welcome singles to consider adopting newborns and within the foster/adoption system. Some foreign countries do allow singles to adopt, and we try to lead you in the direction that is best for you.
Children adopted privately within the U.S. are usually newborns and young infants. Children adopted internationally can range from infants to older children, depending on the adoptive parent's age and specific country requirements.
Some countries and placing agencies do allow you to specify the gender of the child, but some ask that you remain open to a boy or girl. If you are adopting a newborn within the U.S., you must remain open to either gender. You can certainly choose the gender if you adopt through the U.S. foster/adoption system.
Our agency does not place age restrictions on parents, however, we do follow the rules of each country for international adoption. There is more flexibility within domestic adoptions about parental age, so please be encouraged.