Last weekend I wrote a blog post for ScienceNOW about whether “test tube” babies are healthy. Answer: Basically, yes, but the oldest one is only 31, so there’s no way to know about health effects that show up later in life. And there are definitely differences between babies conceived in vitro and babies conceived the natural way. The differences are epigenetic, which means they’re not differences in the genes themselves – they’re related to how the genes get expressed.
This is related to a shift in how people think about biology. For decades after DNA was discovered, everyone was really worked up about the genetic code, and how genes are a blueprint for everything. But the truth is, of course, much more complicated. Just because you have a gene doesn’t mean that it’s being expressed. It might be turned off entirely, or only weakly expressed, or only expressed in some cells and not others. Epigenetics is about looking at differences in how genes are expressed (turned into proteins).
You can understand the blog post even if that doesn’t make sense
Fun fact: They aren’t test tube babies, they’re actually petri dish babies.
Another fun fact: The picture with my story is of an egg being fertilized by intracytoplasmic sperm injection (ICSI) (“icksee”). While in vitro fertilization was developed to get around female infertility, ICSI is for male infertility. As long as the guy is still making some sperm, you can fish them out and inject one right into the egg.