Help needed, linear regression SPSS for birthweight controlling for maternal age

Hello all,

I am in need of help. I am performing a study looking at the effects of Assisted Reproductive Technology on birthweight, and I would like to control for maternal age.

So far I have that ART mothers are significantly older (basically 35.5 vs 31.5 years in my data), and ART babies are significantly lighter (2900 grams vs 3250 grams).

My question is, is there a way to determine what the average birthweight of ART babies is compared to non-ART babies (aka ART yes/no in SPSS), while controlling for maternal age? Is there a way to come up with an average number for both?