I tend to think baby Brookheimer-Egan should be a girl. Admittedly there’s jokes either way – it’s a boy they can riff on Dan and him recreating Selina and Catherine’s relationship (which…eep) – whereas if it’s a girl, the jokes kind of write themselves. Karma’s a bitch.
More to the point, Dan’s child being a girl could (at least theoretically) force some character development – it’ll make Dan face the full implications of how badly he’s treated women over the years. (Though he’s definitely narcissistic enough to assume that HIS daughter will be an exception, no one would ever treat HER badly).
I guess the question is… do they want Dan to develop?
(I can’t see Amy’s behaviour changing much whether the child is male or female, so I don’t think her character development is a factor in whatever decision the writers go with)