There are many parents today who would love to add a little baby girl or boy (specifically) to their family. While I don't typically advocate sex-selected divisions (after all, it is my wish that all genders/sexes would be equally valued - especially as little ones) there are some very basic and very 'natural' ways to influence the conception of your next baby. Having spent years studying and teaching in human sexuality, it sometimes comes as a surprise to me that this information is not common knowledge yet - but then again, most people are probably not as enamored with learning about the birds-and-the-bees as I am...
My own mother used this book long ago - 30+ years! - to get her babies - Girl, Boy, Girl, Boy. It has been used successfully by countless others. And while it may not be the most 'entertaining' of reads - it actually works (most of the time!). The advice found within - when put into practice - greatly increases your own likelihood of your next baby being a boy or girl.
So, if this is something that spikes your interest -- happy baby making!
How to Choose the Sex of Your Baby - L.B. Shettles & D.M. Rorvik