Why Can't Gay Men Mix Sperm During IVF?
There is a commonly spread myth that gay men can "mix" their sperm during IVF. The intended goal of mixing these sources is either to not know who the biological father is or to both have a biological connection to the baby. Unfortunately, this is not how IVF works and for legal and medical reasons the fertility center must know who is the biological connection.
When creating embryos a single sperm is injected into a single egg, therefore there can only be one true biological connection with each baby. But, do not worry, if both intended parents want a biological connection to a child that is possible. The most common way to create this connection is to have both intended parents create embryos using the same egg donor. By doing this, both children will be biologically connected to one another.
For more information on both partners being biological dads, check out this article.