Systems and methods for obtaining biological molecules from a sample

A method of determining the sex of an in utero fetus, the method comprising the steps of:

• obtaining a sample of biofluid from a pregnant mother, wherein the biofluid is selected from the group consisting of:
• blood, plasma, serum, urine, and cerebrospinal fluid, and wherein the sample is stored on a sample collection apparatus, the sample collection apparatus comprises cellulose paper on which the biofluid is placed to dry, and the cellulose paper has not been treated with any chemical stabilizers of nucleic acids;
• extracting nucleic acids from the sample, wherein the nucleic acids are RNA;
• sequencing the extracted nucleic acids to generate sequence data, wherein the RNA is sequenced with RNA-Seq;
• and
• analyzing the sequence data to determine the sex of the in utero fetus, wherein the in utero fetus is male if expression of Y chromosome genes is similar to or greater than expression of X chromosome genes in the sample, wherein analyzing the sequence data comprises:
• processing sequencing reads to remove information related to barcodes and adapters;
• aligning the sequencing reads to reference sequences;
• quantifying the aligned sequencing reads to generate a numerical estimate of each gene's expression or counts;
• and
• determining total counts from Y chromosome genes and total counts from X chromosome genes.