Simply out of ignorance, sometimes friends and even strangers ask questions of adoptive parents that may be offensive. Most adoptive parents have had to offer explanations and, at the same time, educate.
When it comes to adoption questions it is important to understand that those not touched by adoption may just be curious and not quite what is and is not appropriate. Rather than being offended, there are some appropriate answers that will actually help the questioner understand. Keep in mind that most people do not want to offend, but are curious. Some honestly want to learn about adoption. Humor always helps in awkward situations. When sincere understanding is sought after, taking the time to educate a friend in adoption is worth the effort.